Each of the following could be a complete and accurate list of the researchers who learn both Swahili and Yoruba EXCEPT:

Emil-Kunkin on November 23 at 01:28AM

B is correct because we know that P and L must always be together, so we cannot have one without the other.

However there is no reason why we cannot have H as the only one in both S and Y. We could make a valid scenario with H being the only person in both s and y