Following statements have been made about vaccines.

A. Covaxin is a killed cell vaccine and Corbevax is a subunit vaccine.

B. Oral polio vaccine is given as a live attenuated vaccine to adults and as a killed vaccine to children.

C. Third generation vaccines against smallpox are based on attenuated Vaccinia virus.

D. MMR vaccine is given to children to protect them against diphtheria.

Which one of the following options represents the combination of all correct statements?