Answer
C.
Work Step by Step
The big difference between the signals is their affinity or disaffinity for water (C.). D. is the opposite of this and is thus wrong. A. can be eliminated since steroids and peptides are not very different in size, and B. is incorrect since both peptides (up to 20 amino acids in length) and steroids (complexes of rings with side groups attached) can have a range of structures to carry a range of signals.