MCQ
$\left( {\begin{array}{*{20}{c}}n\\{r + 1}\end{array}} \right) + 2\left( {\begin{array}{*{20}{c}}n\\r\end{array}} \right) + \left( {\begin{array}{*{20}{c}}n\\{r - 1}\end{array}} \right) = .......$
- A$\left( {_{\,\,\,r}^{n + 2}} \right)$
- B$\left( {\,_{r + 1}^{n + 2}\,} \right)$
- C$\left( {_{\,\,\,r}^{n + 1}} \right)$
- D$\left( {\,_{r + 1}^{n + 1}\,} \right)$