The answer to the question about how many yellow fish she can see is letter B or four (4). Although looking at the picture, we can only see two fish, but if we are to take into consideration their eyes, two fish both have two eyes, which in turn, make her see four eyes of yellow fish. This is probably the best explanation to the question and the correct answer.
A fish eyes have lens-covered retinas which house rod cells that perceive contrast even in low light and cone cells which provide color to their vision. Here are a few species of fish that have a touch of yellow on their skin: Arabian angelfish, blueface angelfish, cortez angelfish, rock beauty and scribbled angelfish.