The sum of three consecutive even integers is 36. Let x represent the first integer, x + 2 represent the second integer, and x + 4 represent the third integer.
 Which equation can be used to find the first integer?
 a. 2x + 6 = 36
 b. 3x + 6 = 36
 c. 3x + 36 = 2x + 6
 d. 3x = 2x + 6