A

$I=\displaystyle\int_0^1dx\int_0^{\sqrt{1-y}}3x^2y^2dy$

B

$I=\displaystyle\int_0^{\sqrt{1-y}}dx\int_0^13x^2y^2dy$

C

$I=\displaystyle\int_0^1dx\int_0^{1-x^2}3x^2y^2dy$

D

$I=\displaystyle\int_0^1dx\int_0^{1+x^2}3x^2y^2dy$