The Ability of Some Viruses to Remain Inactive (Latent) for a Period

The ability of some viruses to remain inactive (latent) for a period of time is exemplified by

A) influenza, a particular strain of which returns every 10-20 years.
B) herpes simplex viruses (oral or genital) , whose reproduction is triggered by physiological or emotional stress in the host.
C) Kaposi's sarcoma, which causes a skin cancer in people with AIDS, but rarely does so in those not infected by HIV.
D) the virus that causes a form of the common cold, which recurs in patients many times in their lives.
E) myasthenia gravis, an autoimmune disease that blocks muscle contraction from time to time.