Ken bought x boxes of cookies to bring to a party. Each box contains 18 cookies. He decides to keep two boxes. He brings 108 cookies to the party. Which equation can be used to find the number of boxes Ken bought?

A) 18x + 36x = 108
B) 18x − 36x = 108
C) 18x + 36 = 108
D) 18x − 36 = 108