PUREBRED Labrador Retriever (bred for field work).

(So you got this one WRONG! Thank you for subjecting this purebred Labrador Retriever to breed discrimination)

For those who cannot believe this is a purebred Labrador Retriever:

The chocolate on the left is the half brother of the black/tan in the middle. If you look closely at the chocolate dog on the left, you can see that he also has faint tan points. The breeding that produced the black/tan was repeated, and they got another black/tan. The plain chocolate on the right is the daughter of the chocolate on the left.

The AKC standard even references black and tan as a fault for the Labrador Retriever, but if you still need convincing, do some research of your own on mismarkings in purebred Labrador Retrievers.