The value of expression $\large\frac{1-4\sin 10^{\large\circ}\sin 70^{\large\circ}}{2\sin 10^{\large\circ}}$

Question

$(a)\;\large\frac{1}{2}$$\qquad(b)\;1\qquad(c)\;2\qquad(d)\;None\;of\;these$