Answer:
d - 0%
Explanation:
Let curly hair gene be represented by AA
Straight hair gene will be aa
Since a cross between curly and straight hair resulted in wavy hair, it means wavy hair is an heterozygous condition Aa
Crossing wavy hair Aa with straight hair aa.
Offspring's genotype will be: Aa, Aa, aa, aa
Phenotypically, Aa is wavy hair and aa is straight hair, it means none of the offspring will have curly hair (0% probability).
The correct option is d.