Secretariat was one of the most famous racehorses in history. No one knew how Secretariat was able to run so fast and win so many races—until he died. When veterinarians examined Secretariat’s heart, they discovered that it was almost twice the size of the hearts of other racehorses. Secretariat’s large heart, which he had inherited from his mother’s side of the family, enabled him to pump more blood than the hearts of the other horses. Therefore, his cells received more oxygen and he could run faster and longer. What can you most likely infer about Secretariat’s hereditary past?

a
Secretariat’s grandmother on his mother’s side could have had an enlarged heart.
b
Either his mother or his father could have had enlarged hearts.
c
Every one of Secretariat’s ancestors likely had enlarged hearts.
d
Nothing; Secretariat’s heart was large because he ran so much, not because of heredity.