The Salk IPV and the Sabin OPV Differ from One

The Salk IPV and the Sabin OPV differ from one another in that ________.

A) the IPV contains a version of the virus that is fully inactivated,whereas the virus within the OPV is attenuated,that is,reduced virulence but still viable
B) the IPV must be administered by injection,whereas the OPV can be given orally
C) the OPV,being viable,may revert back to the neurovirulent strain and be transmitted to other susceptible individuals,whereas the IPV,being inactivated,cannot revert to a virulent strain
D) children in developing countries are administered the OPV,whereas in the USA,children are given the IPV by injection
E) All of the choices are correct.