The probability that a mother in the top third of the income distribution will have a daughter in a top third of the income distribution equals 0.5. What is the probability that the grand daughter (along the maternal line) of a woman in the top third of the income distribution will herself be in the top third of the income distribution?

a. 0.25

b. 1

C. 0.75

d. 0.5

Give proper calculation with explaination...step by step thank you