Answer:
A. 50%
Explanation:
Using Gregor Mendel's genetics cross, the probability of obtaining brown hair is 50% or 2/4. In Gregor Mendel's genetics cross, the dominant gene represented as Bb is crossed against the recessive, bb. On completing the cross, the products of the cross are two dorminant gene (brown hair) with a trait of red hair and the recessive gene will not be expressed, while the two remaining products are recessive, bb and therefore the recessive gene for red hair will be expressed.
