After Reading the Paragraph Below, Answer the Question(s) That Follow(s)

Multiple Choice

After reading the paragraph below, answer the question(s) that follow(s) .
Desert pupfish live in springs of the American Southwest. Today there are about 30 species of pupfish, but they all evolved from a common Pleistocene ancestor. The southwestern United States was once much wetter than it is now, and the Pleistocene pupfish flourished over a wide geographic area. Over thousands of years, however, the Sierra Nevada mountain range was pushed upward by geological forces, blocking rainfall from the Pacific Ocean. As the large lakes dried up, small groups of pupfish remained in springs and pools fed by groundwater seepage. Now, although many of these small springs still have pupfish, each population has evolved to become very different from pupfish in other springs.
-Individuals of the different pupfish species presumably would not mate with each other even if they were housed together. Which of the following is unlikely to be a possible reason for this?

A) evolved anatomical changes that render the species incompatible
B) evolved behavioural changes that render the species incompatible
C) evolved genetic incompatibilities between egg and sperm
D) evolved changes in the genetic code