What is the impulse response of the given causal LTI system with the associated Z-transform (z) = -2z-¹(1 + 1/2z-¹)(1 + 1/4z-¹)?
a. ℎ[] = 2(1/2)ⁿ - (1/4)ⁿ
b. ℎ[] = -2(1/2)ⁿ + (1/4)ⁿ
c. ℎ[] = -2(1/2)ⁿ - (1/4)ⁿ
d. ℎ[] = 2(1/2)ⁿ + (1/4)ⁿ