How many two-element subsets of {1,2,3,4} are there that do not contain the pair of elements 2 and 4?	Choose one
A) One  B) Two  C) Four  D) Five  E) Six
{1,2}, {1,3}, {1,4}, {2,3}, {3,4}.   Or: C24−1=5   Answer: Five.
<result>D</result>
How many two-element subsets of {1,2,3,4} are there that do not contain the pair of elements 2 and 4?