As per the given condition in the question:

$14 = 13 + 1$ $18 = 17 + 1$ $20 = 19 + 1$ $24 = 23 + 1$ $30 = 29 + 1$ $32 = 31 + 1$ The next prime number after 31 is 37. Therefore,

$37 + 1 = 38$ Hence, option C is the correct answer.