how many two - element subsets of < 1 , 23 , 45 , 67 > are there that do not contain the pair of elements 2 and 4 ?	Choose the correct option
A) 11 B) 12 C) 14 D) 15 E) 20

Rationale: 7 c 2 - 1 = 20 answer is e
Answer: E