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 a subunit of that agent for a vaccine?

A) An attenuated agent strongly stimulates both the humoral AND cell-mediated adaptive immune response, giving the best comprehensive long-term protection available.
B) There is no advantage. It's much more dangerous to use an attenuated agent over a subunit vaccine due to the possibility of reversion of the microbe to a pathogenic state.
C) 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.
D) 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.
E) There is no advantage. If a subunit is used from that agent, all the T cells that are activated will make antibodies against that single antigen, causing a very strong response.