Câu hỏi 4Tính $\left(- a^{2} b^{4} \frac{c}{2}\right)^{3} \div \left(ab^{2} \frac{c}{4}\right)^{2}$.$2 a^{4} b^{2} c^{8}$$- 2 a^{4} b^{6} c^{2}$$- 2 a^{4} b^{2} c^{8}$$- 2 a^{4} b^{8} c$$- 2 a^{4} b^{8} c^{2}$