GMAT CLUB OLYMPICS: In professional boxing matches, boxers compete aga

Explanation

We’ll go for ALTERNATIVE because we are asked to assess which answer choice must be true.

(A) We have no information on the class with the lowest rate, only on that with the highest, so (A) does not HAVE to be true. Note that while the passage does state that the high rate of head injuries per match in the heavyweight class is “attributed” to muscle mass, it does not tell us that this is a strictly linear correlation: we do not know whether less muscle mass always means fewer head injuries, so we cannot conclude anything about the class with the lowest rate.

(B) The passage tells us that boxers compete against boxers in the same weight category. Therefore, the boxers who caused heavyweight boxers to have the highest rate of head injuries per match were other heavyweight boxers! This must be true and is the correct answer. For practice, let’s examine the others.

(C) We do not have information about all sources of danger and cannot say how head injuries compare with everything else.

(D) Without information on the number of matches played per year, we cannot calculate the number of head injuries per year.

(E) is a statement that is perhaps reasonable to infer from the given passage, but does not necessarily derive from it. In other words, it is not necessarily true—maybe larger muscle mass makes hits to the body less effective, so the boxers aim more for the head.