I was quite torn between A and E. For that reason, I will firstly describe my reasoning for eliminating the other options.
Quote:
(B)According to The Stock Trader's Almanac, the performance of stocks in January foretells the
market's performing throughout the year, but statistics experts warn that causation is impossible to prove.
I was not entirely sure whether "market's performing" is acting as possessive or as "is performing". Correct me if I am wrong but I believe GMAT does not use contractions and thus it is acting as possessive.
WrongQuote:
(C)According to The Stock Trader's Almanac, the performance of stocks in January foretells the performance of the
year's market, but statistics experts warn that causation is impossible to prove.
All seems to be well until we get to "year's market". As if there was a market where one could buy "years".
WrongQuote:
(D)According to The Stock Trader's Almanac, the performance of stocks in January foretells what the market will perform like in the year, but statistics experts warn that causation is impossible to prove.
Firstly, we definitively want to use "how will the market perform". The structure "what the XXX will perform" seems to indicate that the market will put on a show (think theater performance). Secondly, "perform like" is an another suspect. Especially when it is used in conjunction with time duration. We cannot substitute "like" for "throughout" or "during".
WrongBetween A and E, I decided to go with E. I wish I had a profound reason why but I really don't. The answer A reminds me of zero conditional that is used for something that is always correct. For instance, if you mix blue and yellow, you get green. Notice, that it does not use "you will get green". Even though this case is not a conditional, the "foretells" seems to signal future. Thus, future simple tense seems to be the best choice.