A supporter would cite something that bolsters the argument.

Conclusion - Wide dissemination of wireless networks in cities is a practical way to meet the needs of city households, schools and businesses

Premise - Rural communities have found that wireless networks are both more reliable and cheaper than land-based networks.

One can 'directionally' prephrase the answer, we have to prove that wireless dissemination in cities is a good idea and the evidence given to support it is that it works well in rural areas, if somehow we can link the rural wireless effectiveness to the urban setting we are good to go!

Moving to the answer choices.
A - Good! Makes the connection between rural and urban conditions. Mark as a contender
B - Oops! If wireless works better in low density areas (aka rural areas) it is a problem, because cities might not be low density areas. Hence reject.
C - Great that Iceland uses wireless and it is rural but it still misses the rural to urban connect. Hence reject.
D - Nah! It this is true wireless in cities not a good idea.
E - The argument is not about rich or poor neighborhoods, it is about wireless in cities. This choice is way off the mark.

Hence pick A

Tactical notes for the exam:
It might not be possible to prephrase in such a fashion all the time, but actively try out such tactics for two reasons:
1. It keeps you actively engageded while reading
2. You might save time as you can select a correct answer much faster

Hope this helps, the idea is to get this question right and learn something from this to get the next one right as well!