Answer:
Simple Random
Explanation:
Canine parvovirus is a disease that mainly spreads through contact with feces. It can be assumed that if one of the eight dogs is infected the rest will have it too.
The method by which Will is told to pick a dog is completely random. There is no reasoning behind which dog he will pick. Just the first dog which will touch his hand. Each dog has an equal probability of being selected.
Hence, the vet suggested simple random sampling to Will.