A Man with Pubic Lice Uses an Over-The-Counter Insecticide to Remove

A man with pubic lice uses an over-the-counter insecticide to remove them. He is fine for about a week, but then begins itching again. What is the most likely reason?

A) The insecticide only killed some of the lice.
B) The insecticide weakened the lice, but they recovered.
C) The treated lice fell off his body and survived in his bedding for a week.
D) The man encountered another person with lice and he got them again.
E) The insecticide killed the adult lice, but the nits survived and hatched.