How many even integers n, such that 20<=n<=220 are of the form 3k+4, where k is any natural number?  Choose the most appropriate option.
A) 28 B) 31 C) 34 D) 37 E) 40

Rationale: "the first number is 22 = 16 + 6 ( 1 ) . we can continue adding 6 to make a list : 22 , 28 , 34 , . . . the last number is 220 = 16 + 6 ( 34 ) there are 34 numbers in the list . the answer is c ."
Answer: C