When Thomas Hunt Morgan conducted dihybrid crosses with his fruit flies, which of the following made him realize that the two genes he was observing were linked, or inherited together as a group?

a)The dihybrid F ratio was close to a 3:1 ratio.

b)The dihybrid F ratio followed Gregor Mendel’s 9:3:3:1 phenotypic ratio.

c)The dihybrid F ratio followed Gregor Mendel’s 1:2:1 phenotypic ratio.

d)The dihybrid F ratio demonstrated a strict 1:1:1:1 phenotypic ratio.