$\sqrt 2 - cosec20^{\circ}- \sec 20^{\circ}=$

Question

$$\begin {array} {1 1} (1)\;2 & \quad (2)\;2 \sin 20^{\circ}. cosec 40^{\circ} \\ (3)\;4 & \quad (4)\;4\; \sin 20^{\circ}. cosec 40^{\circ} \end {array}$$