Study the given pattern carefully and select the number that can replace the question mark (?) in it.

Logic: The upper number squared gives the two lower numbers as digits.

First Figure:
Upper Number: 6
Lower Numbers: 3, 6
6² = 36
=36 → Digits 3 and 6
Second Figure:
Upper Number: 5
Lower Numbers: 2, 5
5² = 25
= 25 → Digits 2 and 5
Third Figure:
Upper Number: ?
Lower Numbers: 1, 6

The number squared should give 16.
?² = 16
? = $$\sqrt{16}$$​​
? = 4
Thus, the correct option is (d) 4​​