If $^nC_r$ denotes the number of combinations of $n$ things taken $r$ at a time,then the expression $^nC_{r+1} + ^nC_{r-1} + 2 \times ^nC_r$ equals
- A$^{n+2}C_r$
- B$^{n+2}C_{r+1}$
- C$^{n+1}C_r$
- D$^{n+1}C_{r+1}$
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