Which of the Following Statements Is True About the Production

Which of the following statements is True about the production of the influenza vaccine?

A) Viruses are injected into fertilized eggs, incubated, then viral particles are extracted, purified, deactivated, and used to make vaccines.
B) Viruses are injected into mammalian cells, then viral particles are extracted, purified, deactivated, and used to make vaccines.
C) A protein responsible for the H spikes of the flu virus is added to a harmless virus that infects insect cells, causing them to produce massive amounts of H spike protein. The extracted H spike protein is then purified and used to make vaccines.
D) All three methods describe different approaches used to make flu vaccines.