The curve $y=a x^{2}+b x+c$ passes through the point $(1,2)$ and its tangent at origin is the line $y=x$. The area bounded by the curve, the ordinate of the curve at minima and the tangent line is
(a) $\frac{1}{24}$
(b) $\frac{1}{12}$
(c) $\frac{1}{8}$
(d) $\frac{1}{6}$