Which of the following statements is a good explanation for the observation that many different rhinovirus strains can all use the same host cell receptor?

A) The receptor binding site is buried at the base of a narrow canyon on the viral capsid which is inaccessible to antibody proteins.
B) The recptor binding site is the most exposed area of the capsid which is highly accessible to antibody proteins.
C) The amino acid sequence of the canyon region of the capsid is highly variable.
D) The amino acid sequence on the antibody exposed surfaces of the capsid is highly variable.
E) The amino acid sequence on the exposed areas of the capsid are highly conserved in each strain.