GMAT Critical Reasoning (CR) | Re: The difference in average annual income in favor of employees who have

A) is the gmat answer. Here is why it is wrong.

The hypothesis is that increased competition for employees drove up income. Ie, At its essence that a supply demand in imbalance vis a vis roles for college graduates vs supply of graduates caused wages to rise and that this rise continued over the 1980s.

A is wrong for the following reasons

1)First of all "a growing %".