In the A.P., 5, 7, 9, 11, 13, 15, ... the sixth term which is prime is

If we see that, in the given series, d = 2

So if e continue the series, we get :

5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25 …….

We can see that, the prime nos. In the above are :

5, 7, 11, 13, 17, 19, 23, …

so here we see that the sixth term which is prime is 19

∴ the correct option is (b)