Answer: Option D. "Toxoid"
Step-by-step explanation:
Inactivated polio vaccine (IPV) is defined as the polio vaccines which are used to prevent poliomyelitis.
IPV is produced from wild-type poliovirus strains and then they are allow to inactivated (killed) with formalin.
Toxoid vaccines is an example of IPV, which is made by inactivating the toxin that is responsible for disease symptoms and allowed an immune response against the toxin without any harm to the body. Toxoid vaccines are available for several immunizations including the tetanus and diphtheria immunizations.
Hence, the correct option is D.