Suppose f is such , that $f(-x) =-(x)$ for every real x and $\int\limits_0^1 f(x)x=5$ then $\int \limits _{-1}^0 =?$

Question

$$\begin {array} {1 1} (a)\;20 \\ (b)\;5 \\ (c)\;0 \\ (d)\;-5 \end {array}$$