Two Populations of Snails Are Allopatric, Living in Areas That

Two populations of snails are allopatric, living in areas that have different compositions of soil types.The snails live in soil and are not very mobile.Researchers are interested in whether the populations have acquired different types of reproductive isolation.Which method would be best to determine whether two populations exhibited behavioral isolation?

A) Move them into a common experimental setting to see if they will produce offspring. If they produce offspring, they exhibit behavioral isolation.
B) Move them into a common experimental setting to see if they will produce offspring. If they do not produce offspring, they exhibit behavioral isolation.
C) Bring them into the lab. Observe single pairs of a male from one population and a female from the other. If they mate, then they exhibit behavioral isolation.
D) Bring them into the lab. Observe single pairs of a male from one population and a female from the other. If they do not mate, then they exhibit behavioral isolation.
E) Observe when each population is active. If they are active at the same time, then they exhibit behavioral isolation.