Question

Which of the following are correct

There are enough MAs and Ph.D.s in here to fill a college.
There are enough MA's and Ph.D.'s in here to fill a college.
both

Answer 1

The correct answer is #1

There are enough MAs and Ph.D.s in here to fill a college.

Answer 2

The second one is correct.

There are enough MA's and Ph.D.'s in here to fill a college.

There should always be an apostrophe when you want to make any of these abbreviations, plural.