When a Parasite First Invades a Host, It May Be

When a parasite first invades a host, it may be very damaging, even causing the host's death.Over many generations, the host-parasite relationship may evolve so that the parasite's effect on the host is much weaker.How would this evolution most likely affect the size of the parasite population?

A) It would increase because the less-damaging parasites would require less food.
B) It would decrease because the host would fight off less-damaging parasites.
C) It would decrease because the parasites would leave to find hosts they could damage more.
D) It would increase because more hosts would survive and be available for more parasites to infect.
E) It would remain the same because relative effects of the parasite do not affect population size.