Explanation:

Option 2nd is correct.

• Housefly is not a parasite. The housefly, Musca domestica, is a common household pest known to transmit human diseases like pathogenic bacteria, protozoa, metazoan, fungi and viruses. Apart from they are also responsible for transmitting intestinal parasites, which when outbreaks occur, could wreak havoc on both man and animals.

• Head louse (Pediculus humanus capitis) is an obligate parasite. It causes head lice infestation.

• Ticks are parasites that feed on warm-blooded hosts by biting them. A tick bite can infect humans and animals with bacteria, viruses and protozoans (organisms made up of one cell) that can cause diseases. 

• Bed bugs (Cimex lectularius) are small, flat, parasitic insects that feed solely on the blood of people and animals while they sleep. Bed bugs are reddish-brown in color, wingless, range from 1mm to 7mm (roughly the size of Lincoln's head on a penny), and can live several months without a blood meal.