Answer:
The correct answer is option D. "has evolved to become less lethal; have evolved resistance".
Step-by-step explanation:
The Myxoma virus is a type of poxvirus that originated from South America, it developed on rabbits and it is transmitted by mosquitoes. The virus was purposely introduced to Australia during the 1950s to control the population of rabbits. In the first years the virus was efficient and reduced the population of rabbits from 600 to 100 millions, however, in the following years the virus has evolved to become less lethal and rabbits have evolved resistance to the virus, allowing a partial rebound of the rabbits' population.