Answer:
Option D
Step-by-step explanation:
In the general process of producing vaccines for any viral diseases, the viruses are cultivated in any carrier animal such as hen and then these virus fluids are extracted from the body of the test species. The virus in the virus solutions are inactivated (killed) and the virus solution i.e antigen is cleaned , purified and tested to make vaccines for influenza virus.
Hence, option D is correct