MCQ
Let $f:[-1,2] \rightarrow[0, \infty)$ be a continuous function such that $f(x)=f(1-x)$ for all $x \in[-1,2]$. Let $R_1=\int_{-1}^2 x f(x) d x$, and $R_2$ be the area of the region bounded by $y=f(x), x=-1, x=2$, and the $x$-axis. Then
- A$R_1=2 R_2$
- B$R_1=3 R_2$
- ✓$2 R_1=R_2$
- D$3 R_1=R_2$
