Final answer:
Components of vaccines can include attenuated viruses and bacterial proteins. Live, pathogenic bacterial cells are not typically used as vaccine components. Therefore, options b and c are correct answers.
Step-by-step explanation:
The components of a vaccine can include various biological components such as:
Attenuated viruses, which are weakened strains of viruses used to establish a subclinical infection that activates the adaptive immune defenses.
Bacterial proteins, which are one of the key antigens used in subunit vaccines to elicit an immune response without using whole live or inactivated pathogens.
Live, pathogenic bacterial cells are not typically used in vaccines due to the danger they pose to the host.
Therefore, options b and c from the student's question list can be used as components for vaccines, but not option a. Among the listed vaccine types, live attenuated vaccines and subunit vaccines are specifically used. Live attenuated vaccines are created through processes that diminish the pathogen's ability to cause disease but keep them alive, such as genetic manipulation or culturing under specific conditions. In contrast, subunit vaccines include elements like bacterial proteins which are either isolated from the real pathogens or genetically engineered.