What is the expression in radical form? (7x³y²)²7 Enter your answer, in simplest form, in the box.
a) 7√(x⁸1y⁵4)
b) 7√(x⁸1y¹08)
c) 49√(x⁸1y⁵4)
d) 49√(x⁸1y¹08)