C but it's still not exactly correct, they would just be definite carriers of the colour blind trait but only the girls are able to obtain the gene
The answer to this question is lactic acid. The reason why sports psychologists would need to look for a buildup of this chemical is because it is the chemical that produces pain or "feeling the burn" in an exercise when someone pushes their limit. Also, after so long, a person with a lactic acid buildup needs to take a break because high levels of lactic acid is dangerous for the bloodstream.