Simplify: \rt[4]16x8y12\rt[4]{16x^8 y^{12}}\rt[4]16x8y12.
2x2y32x^2 y^32x2y3
4x2y34x^2 y^34x2y3
2x4y82x^4 y^82x4y8
16x2y316x^2 y^316x2y3