Neuroscientists Study the Nervous Systems of Other Animals Such as Slugs,snails,fruit

Neuroscientists study the nervous systems of other animals such as slugs,snails,fruit flies,rats and monkeys because:

A) if all animals are related then all nervous systems are related and we can learn about the human brain by studying other animals.
B) all animals' nervous systems are different,which means that we need to study each animal separately in order to understand how their specific nervous system works.
C) the mind and the body are separate which means that we need to study a variety of different animals to see how their minds work.
D) None of the answers is correct.