Scientists once believed that the oversized head, long hind legs

Scientists once believed that the oversized head, long hind legs, and tiny forelimbs that characterized Tyrannosaurus rex developed in order to accommodate the great size and weight of this prehistoric predator. However, this belief must now be abandoned. The nearly complete skeleton of an earlier dinosaur has recently been discovered. This specimen had the characteristic T. rex features but was one-fifth the size and one-hundredth the weight.

The answer to which one of the following questions would most help in evaluating the argument?

(A) Was the ratio of the head size of the recently discovered dinosaur to its body size the same as that for T. rex?

(B) At what stage in its life did the recently discovered dinosaur die?

(C) Was T. rex the largest and heaviest prehistoric predator?

(D) Was the species to which the recently discovered dinosaur belonged related to T rex?

(E) Did the recently discovered dinosaur prey on species as large as those that T rex preyed on?

Source: LSAT 80, December 2016