Find all rational zeros of the polynomial function h(x)=x⁴-4x³-46x²-89x-42.
a. ±1, ±2, ±3, ±6
b. ±1/2, ±1, ±3/2, ±2
c. ±1, ±2, ±7, ±14
d. ±1/2, ±1, ±7/2, ±3