The credited response is B.
This is a logical reasoning question from the June 1999 LSAT (question # 17 of the third section within the test).
There is a portion of the stimulus that was not included in the original post.
The stimulus should read as follows:
In 1992, a major newspaper circulated throughout North America paid its reporters an average salary that was
much lower than the average salary paid by its principle competitors to their reporters. An executive of the newspaper argued that this practice was justified, since any shortfall that might exist in the reporters' salaries is fully compensated by the valuable training they receive through their assignments.
I didn't like any of the answers, but narrowed my selection down to A and B, finally guessing A. I really didn't like B (I think I may have over thought this answer choice) because, to me, it seemed perfectly reasonable to believe that the reporters could continue to gain experience after having worked with the paper for more than ten years. While the weakening effects of A seemed negligible, B (at the time) seemed wholly irrelevant.
My biggest issue with B is that it requires the test taker to make the assumption that no more experience can be gained after 10 years of work.
This entire section of the test seemed to be filled with some pretty terrible crafted questions, # 17 being no exception.