The correct option is A 4(x−2)
P(x) = 8(x4−16)=23(x2−4)(x2+4)=23(x−2)(x+2)(x2+4)
Q(x) =12(x3−8)=22× 3× (x−2)(x2+2x+4)
The common irreducible factors of P(x) and Q(x) are 2 and (x-2)
The smallest exponents of these factors in P(x) and Q(x) are 2 and 1 respectively.
Hence, the HCF = 22× (x−2)=4(x−2).