All of the following statements about childhood immunizations are accurate except

a. it has been proven that the vaccine for measles-mumps-rubella does not cause autism
b. only the first of the recommended doses for each vaccine needs to be given
c. the consequences of contagious diseases, such as whooping cough, measles, and mumps, are worse than the pain of being inoculated with vaccines against those disease
d. although many contagious diseases have become rare in the general U.S. population, immunizations should still be given for those diseases

B