Indian Institute of Foreign Trade 2015 Solved Paper

(d) Substituting the values given in the options directly in the equation.
1 and 2 get eliminated as inside the root –ve value cant's be possible. and on putting n = 4 in the equation.
we get $\sqrt{4\times 4\mathit{–}9}+\sqrt{4\times 4+9}=5+\sqrt{7}$