Correct Answer - Option 1 : 121
The logic follows here is;
[First Number + √(Second Number)]2 = Third Number
In 4 + 25 = 81:
(4 + √25)2
= (4 + 5)2 = 92
= 92 = 81
In 9 + 49 = 256:
(9 + √49)2
= (9 + 7)2
= 162 = 256
In 7 + 16
(7 + √16)2
= (7 + 4)2
= 112 = 121
Hence, "121" is the correct answer.