Choose the correct answer in the the area bounded by the $y$ - axis, $y = \cos\: x$ and $y = \sin\: x$ when $0 \leq x \leq \frac{\large \pi}{2}$ is

Question

$$(A) 2 (\sqrt{2-1}) \qquad (B) \sqrt 2 - 1 \qquad (C) \sqrt 2 + 1 \qquad (D) \sqrt 2$$