The value of (1 - √2) + (√2 - √3) + (√3 - √4) + . . . . . . + ( 15 - 16 ) is-

Answer: Option C

$$\begin{array}{rl}& \text{Expression}\\ & =\left(1-\sqrt{2}\right)+\left(\sqrt{2}-\sqrt{3}\right)+\left(\sqrt{3}-\sqrt{4}\right)+....+\left(\sqrt{15}-\sqrt{16}\right)\\ & =1-\sqrt{2}+\sqrt{2}-\sqrt{3}+\sqrt{3}-\sqrt{4}+....+\sqrt{15}-\sqrt{16}\\ & =1-\sqrt{16}\\ & =1-4\\ & =-3\end{array}$$