It Takes Very Few Molecules of a Hormone to Cause

It takes very few molecules of a hormone to cause changes in a target cell. This may be explained by the fact that:

A) activation of transcription produces many copies of mRNA, and each copy is translated many times.
B) the mechanism of hormonal action involves the replication of the hormone within the target cell to quickly magnify the hormone's effect.
C) hormones are large molecules that persist for years and can repeatedly stimulate the same cell.
D) the mechanism of hormonal action involves an enzyme cascade that amplifies the response to a hormone.
E) the mechanism of hormonal action involves memory cells that have had prior contact with the hormone and immediately respond to its presence.