Context: This passage describes the Thomsen disease trait in humans:
Thomsen disease is a condition that causes temporary muscle stiffness. When a human with Thomsen disease first contracts a resting muscle, the muscle is slow to relax and may stay contracted for a while. But after repeated use, the muscle can contract and relax normally. This is known as the warm-up effect.
In a group of humans, some individuals have Thomsen disease and others do not. In this group, the gene for the Thomsen disease trait has two alleles. The allele for not having Thomsen disease (m) is recessive to the allele for having Thomsen disease (M).
This Punnett square shows a cross between two humans.
What is the expected ratio of offspring that have Thomsen disease to offspring that do not have Thomsen disease? Choose the most likely ratio.
A. 2:2
B. 4:0
C. 0:4
D. 3:1
E. 1:3
From the given choices, pick the correct answer and respond by indicating the letter of the correct option.

A