If in a A.P fourth and seventh terms are 3a+2d and 4a+4d, then what is the nineteenth term?

If in a A.P fourth and seventh terms are $3a+2d$ and $4a+4d$, then what is the nineteenth term?

(A) $8a+12d$ (B) $7a+12d$ (C) $8a+13d$ (D) $7a+13d$ solution: