Answer:
C
Explanation:
The F2 offspring of a cross would follow the ratio of 9:3:3:1 only if the cross is a dihybrid for two unlinked traits.
There is nothing like a monohybrid cross for two traits. A cross involving two traits is a dihybrid cross. Hence, options a and b are out of the equation.
A dihybrid cross for two closely linked traits would produce F2 offspring in another ratio that is different from 9:3:3:1 depending on the linkage map.
Hence, the correct option is C.
