# If $f: R \to R$ is defined by $f(x)= \left\{ \begin{array}{1 1} \large\frac{x+2}{x^2-3x+2} & \quad if & \quad x\in R -[-1,-2] \\ -1 & \quad if & \quad x=-2 \\ 0 & \quad if & \quad x=-1 \end{array} \right.$ then $f$ is continuous on the set :
$\begin {array} {1 1} (a)\;R & \quad (b)\;R-\{-2\} \\ (c)\;R-\{-1\} & \quad (d)\;R-\{-1,-2\} \end {array}$