Okay, looking at this one, you have several difficult verb tenses that need to be in place to get the meaning correct.
The first phrase is conditional, beginning with if. The second is future conditional, with 'I would recommend'. Third, is present perfect.

This example is about picking the correct conditional tense that agrees with the rest of the verb tenses in the example sentence.

A -- Wrong verb tense. 'was' is wrong because this sentence is constructed so that the verb needs to be in the subjunctive tense. The subjunctive is used in conditional or hypothetical cases. Although there is some argument that 'was' is fine and you will hear people say that, the formal and GMAT approved way to construct this is using 'were'. In the subjunctive, it's:

I were
you were
he/she/it were
we were
they were

B -- correct

C -- it's in past tense, which doesn't agree with rest of the verb tenses in the sentence. It says that he already decided not to go to Wall Street, so why does it matter what you would recommend on Wall Street?

D -- Although the verb is not technically conditional, the idiom "in the event" makes the phrase conditional. This is the wrong answer because it's wordy.

E -- same as A

Please let me know if this anwered your question.