Sentence Correction

the biggest problem with choice (b) is the following incorrect parallelism:

taking vitamin E in excess of that found naturally in a balanced diet

the problem here is that this construction is "X in excess of Y". for this construction to be used properly, both "X" and "Y" must be quantitative (i.e., they must be things that can be signified by numerical measurements), since "in excess of" is a mathematical comparison.

in the correct answer (a), this condition is satisfied:
* an intake of vitamin E is a quantitative measurement
* that found naturally in a balanced diet (in which "that" stands for "intake of vitamin E") is also a quantitative measurement

in (b) this condition is not satisfied:
* neither "taking vitamin E" nor "vitamin E" is a quantitative measurement

this is the biggest problem with choice (b).

rohu27 wrote:Suggest and may cant go together? I just took the CAT yesterday and its still the same(the Q).
I dont see whts the problem with suggest and may?
Can you please give another example?

Thanks.

it's an issue of redundancy - both of those words suggest a certain degree of uncertainty, so it's inappropriate to use them together.
as a similar example, you would also want to refrain from using "possible" and "might" in the same thought. for instance, you can say
it's possible that i will go to sleep early today
or you can say
i may go to sleep early today

... but an expression using both of these would be redundant; i.e., you would not write
it is possible that i may go to sleep early today. (WRONG)

the general principle here is economy of expression, but, if you prefer to think in more mathematical terms, you can think of this as analogous to how it's inappropriate to use two of the same function sign when you only want to execute the function once; e.g. if you just want to take the square root of x, then it's inappropriate to write √(√x).