While You're Walking Your Dog,you Observe Two Snails Interacting on a Turf

Multiple Choice

While you're walking your dog,you observe two snails interacting on a turf of grass.You recognize that they are two separate species.The two individuals are attempting to mate,but the direction of the turn in the shell prevents the two species from successfully mating.This is an example of:

A) Allopatric speciation
B) Novel speciation
C) A pre-zygotic barrier
D) A post-zygotic barrier