Poliovirus is most often transmitted viaa) contaminated waterb) endosporesc) mosquitoesd) household petse) droplets

A) contaminated water

Explanation:

Poliovirus is the virus belonging to the genus Enterovirus, family Picornaviridae, composed of three serotypes: I, II and III. It is a spherical, uncoated, single-stranded RNA compound virus, 24-30 nm in diameter.

Poliovirus is the cause of polio and can be transmitted through contaminated food and water or through direct contact with an infected person. The disease is so contagious that it can be caught in the air, especially by people who live with the virus. Who has polio can transmit the disease weeks after infection.

i think it's the first one because doctors aren't the ones who get rid of the old needles. most of them time it's not even doctors who give you shots, it's nurses.