Herd immunity for infectious diseases

All of the following are true about the Herd Immunity for infectious diseases except:
A. It refers to group protection beyond what is afforded by the protection of immunized individuals
B. lt is likely to be more for infections that do not have a sub clinical phase
C. It is affected by the presence and distribution of alternative animal hosts
D. In the case of tetanus it does not protect the individual

Correct answer : B. lt is likely to be more for infections that do not have a sub clinical phase

Herd immunity is more in case of infections with a sub clinical phase