Which preparations use toxoids but not live viruses?

The correct answer focuses on the specific nature of toxoid vaccines, which are created from toxin molecules produced by pathogens rather than the pathogens themselves. Toxoids stimulate an immune response without causing disease because they are inactivated forms of the toxins, not live viruses.

In this case, the preparations mentioned in the selected option include diphtheria and tetanus vaccines, which are both derived from toxoids. The diphtheria vaccine is made from the inactivated toxin of Corynebacterium diphtheriae, and the tetanus vaccine comes from the inactivated toxin of Clostridium tetani. Both of these vaccines effectively elicit an immune response without using live pathogens.

In contrast, the other options consist of vaccines that contain live attenuated viruses or whole virus particles, which do not fit the criteria of using toxoids exclusively. For example, the rotavirus vaccine and the measles, mumps, and rubella virus vaccine contain live attenuated forms of their respective viruses. The varicella virus vaccine also falls into this category as it utilizes a live attenuated version of the varicella (chickenpox) virus.

Therefore, option C accurately describes a group of vaccines that utilize toxoids for immunization, while the