The correct option is A (x2+1)(x2−1)
First, we write all expressions as a product of their prime numbers.
So, x2−1=(x−1)×(x+1)
x2+1=1×(x2+1)
x4−1=(x−1)×(x+1)×(x2+1)
We then choose each prime number with the greatest power and multiply them to get the LCM.
=>LCM=(x−1)×(x+1)×(x2+1)=(x2−1)(x2+1)