Consider the function

$f(x)=sinx+1$

Graph $f(x)$ over the interval $-,.$ Partition the interval into four subintervals of equal length. Then add to your sketch the rectangles associated with the Riemann sum

${\displaystyle \underset{k=1}{\overset{4}{}}}f(c_k)x_k$

given that $c_k$ is either the left$-$hand endpoint, the right$-$hand endpoint, or the midpoint of the interval, and specify which one you chose.