C fits perfectly. The conclusion is that wind power is better source of energy for rural developments than are other sources of energy. If wind power is actually many times more expensive, then it may not be the best choice.

The trick here is that the stimulus offers a fairly broad conclusion (wind power is the best!) from a rather specific premise (wind power pollutes less than other green energy alternatives). It's a fairly common setup, and when we see it we should be ready to take note of other factors (like finances in this case) that could affect the validity of the conclusion.

can you pls explain why A is wrong in this.

heymayank08 wrote:can you pls explain why A is wrong in this.

A might deviate one to think that reports are not reliable because conclusion is varied but it might be the case that this report is more research and hence reliable. Since nothing is given it can be either way, so A DOES NOT AFFECT as it can strengthen or weaken.

Although i agree 99.999% with my statements above, Better strategy would be to keep such options till you find a better option because it might happen (rarely) that in GMAT no better option is available then we can more ponder on such statements.

Experts may comment on my understanding and strategy

A vs C, IMO: C

but in this case it is nowhere mentioned that the low cost will be favourable.
instead we are assuming it.
but assuming in case of CR is a big mistake isn't it!
and option A is not even out of scope of the argument so
i would say that the option A is the best

heymayank08 wrote:but in this case it is nowhere mentioned that the low cost will be favourable.
instead we are assuming it.
but assuming in case of CR is a big mistake isn't it!
and option A is not even out of scope of the argument so
i would say that the option A is the best

We are not assuming it. In fact you can refer to section description of CR from any OG where it is mentioned that question would require you to apply common sense. There is silver-line difference between assumption and common sense. "Low cost will be favorable" is common sense after all EVERYONE WORLD (including you and me) wants to SAVE MONEY, don't we

(A) An earlier Environmental Impact Coalition report showed that solar power produces fewer pollutants than does wind power. This does not weaken. An earlier report is not relevant.
(B) In the last five years, the government has invested more in wind power than in any other form of green energy. Does not weaken. COST ANGLE Incorrect option. One of GMAT's most frequently used incorrect AO
(C) The dispersion of homes in rural areas makes wind power several times more expensive that conventional energy sources. Weakens. Might be more expensive in rural area.
(D) The difference between the number of pollutants generated by wind power and conventional power sources is quite pronounced.NOT RELEVANT
(E) The Environmental Impact Coalition issues reports only once a year. NOT RELEVANT TO CONCLUSION

An Environmental Impact Coalition report shows that wind power produces the fewest pollutants among all green energy alternatives. This shows that EnergyMill wind turbines are the best choice for powering new developments in rural areas.

Which of the following, if true, most seriously weakens the argument in the advertisement?
(A) An earlier Environmental Impact Coalition report showed that solar power produces fewer pollutants than does wind power.
(B) In the last five years, the government has invested more in wind power than in any other form of green energy.
(C) The dispersion of homes in rural areas makes wind power several times more expensive that conventional energy sources.
(D) The difference between the number of pollutants generated by wind power and conventional power sources is quite pronounced.
(E) The Environmental Impact Coalition issues reports only once a year.

Remember that the conclusion or the decision is to be taken based on the current report and not based on the previous reports...

Just like this year's election will decide which party will get selected and not the previous reports.

Option A: From the above perspective, this option does not affect the argument.

Option B: Strengthens the argument.

Option C: Weakens the argument.

Option D: Strengthens the argument.

Option E: Does not affect the argument.

Hence the correct answer is C.

Just to understand that whether this year's report will help or the previous reports will...

Hope this helps...