The Bui family consists of 2 adults and 3 children. They spent $36 for zoo tickets. The equation 2x + 3y = 36 describes the cost for x adult tickets and y child tickets. Part of the equation is graphed below. What is the y-intercept?

On a coordinate plane, a line goes through points (6, 8) and (12, 4).
(0, 12)
(0, 18)
(12, 0)
(18, 0)