Simplify the expression: $$\sqrt{(9 + 4\sqrt{5})}$$​​

Correct option is A

Given:
​$$\sqrt{(9 + 4\sqrt{5})}$$ 
Formula Used:
(a − b)² = a² + b² − 2ab
Solution:
​$$\sqrt{(9 + 4\sqrt{5})}\\= \sqrt{(5 + 4 + 4\sqrt{5})}\\= \sqrt{(\sqrt{5}^2 + 2^2 + 2 \times 2 \times \sqrt{5})}\\= \sqrt{(\sqrt{5} + 2)^2}\\= \sqrt{5} + 2\\$$​​