What Would Be a Primary Advantage of Using an Attenuated

Multiple Choice

What would be a primary advantage of using an attenuated agent rather than just an antigen from that agent for a vaccine?

A) This is actually a disadvantage-it's much more dangerous to use an attenuated agent over a subunit (single antigen) vaccine due to the possibility of reversion of the microbe to a pathogenic state.
B) An attenuated agent strongly stimulates ONLY the antibody production (humoral response) of the adaptive immune system.This provides the best and strongest long-term protection.
C) An attenuated agent strongly stimulates ONLY the cytotoxic T cell (CTL,cell-mediated) side of the adaptive immune system.This provides the best and strongest long-term protection.
D) An attenuated agent strongly stimulates both the humoral (antibody) AND cell-mediated (T cell) portions of the adaptive immune response,giving the best comprehensive long-term protection available.