In West Calverton, most pet stores sell exotic birds, and most of thos

We have several statements about pet stores in West Calverton:

Most pet stores sell exotic birds.
Most pet stores that sell exotic birds also sell tropical fish.
Any pet store that sells tropical fish but not exotic birds does sell gerbils.
No independently owned pet store sells gerbils.
We need to find the answer that must be true based on this information.

Explanation of Answer Choices:
(A) Most pet stores in West Calverton that are not independently owned do not sell exotic birds.

Incorrect. There’s no information about the proportion of exotic bird sales at non-independently owned stores, so we cannot conclude this.
(B) No pet stores in West Calverton that sell tropical fish and exotic birds sell gerbils.

Incorrect. While we know that stores selling tropical fish but not exotic birds sell gerbils, there is no rule preventing stores that sell both tropical fish and exotic birds from selling gerbils. This cannot be concluded.
(C) Some pet stores in West Calverton that sell gerbils also sell exotic birds.

Incorrect. We know that any pet store that sells gerbils must also sell tropical fish but not exotic birds. Therefore, no gerbil-selling store sells exotic birds.
(D) No independently owned pet store in West Calverton sells tropical fish but not exotic birds.

Correct. Any store that sells tropical fish but not exotic birds must sell gerbils, and we know that no independently owned pet stores sell gerbils. Therefore, no independently owned pet store can sell tropical fish without also selling exotic birds.
(E) Any independently owned pet store in West Calverton that does not sell tropical fish sells exotic birds.

Incorrect. There’s no information to support this claim. Some independently owned stores might sell neither tropical fish nor exotic birds.