What should be the next term in the series 2, 3, 6, 6, 10, 9, 14, 12, ___ ?

This is an alternating series in which the terms at odd and even positions follow different rules.   Odd terms à Starting with 2, you get the next term by adding 4 to the previous term at an odd position. So, 2, (2+4) = 6, (6+4) = 10 and so on.   Even terms à Starting with 3 you keep going up in multiples of 3 at every subsequent even positions. So, 3, 6, 9, 12, and so on.   Since the next term is at an odd position, it will be equal to 14+4 = 18.   Hence, the correct answer is option (D).