The correct option is D {√2×√5,100}
We require pairs of numbers for which square of one number is square root of the other number.
For {4,256},
42=16
√256=2×2×2×2×2×2×2×2
⇒√256=(2×2×2×2)×(2×2×2×2)
⇒√256=162
∴ This is a possible pair.
Simlarly, other such pair is: {√3,9}
⇒(√3)2=3=√9
Similiarly, {√2×√5,100}⇒(√2×√5)2=(√10)2=10=√100