question_answer

If the sum of the first m, n, r terms of an A.P. are a, b, c respectively, then\[\frac{\mathbf{a}}{\mathbf{3}}\mathbf{(n-r)+}\frac{\mathbf{b}}{\mathbf{n}}\mathbf{(r-m)+}\frac{\mathbf{c}}{\mathbf{r}}\mathbf{(m-n)}\] equals to ________

A) 0   

B)                                                                    1

C) m + n + r       

D)                                            2

E) None of these