Which of the following most logically completes the argument? A. the minimum acceleration in physical growth that would indicate adolescence might differ according to species B. the fossil record, though steadily expanding, will always remain incomplete C. detecting the adolescent growth spurt requires measurements on the same individual at different ages D. complete skeletons of extinct hominids are extremely rare E. human beings might be the first species to benefit from the survival advantages, if any, conferred by adolescence