The term to be added to 121a2 + 64b2 to make a perfect square is?

Answer: Option A

$$\begin{array}{rl}& \text{121}{a}^2+64b^2\\ & ={\left(11a\right)}^2+{\left(8b\right)}^2+2\times 11a\times 8b\\ & ={\left(11a+8b\right)}^2\end{array}$$
∴ So, term added to make perfect square = 176 ab