The solution of a system, in graphic terms, is where the lines intersect. Ordered pairs follow this form (x,y). Note that all x values are on the horizontal line (think of running when you think of x) and all y values are on the vertical line (think of jumping when you think of y).
According to the graph, y is 0 since the inserect is directly on the x-axis. So (-,0). Cross out A and C because these answer choices do not have '0' as their y-value. This leaves (1/2,0) or (1/3,0). The answer that seems most likely is D. 0.5 (1/2) is closer to 1, and can rounded to 1, opposed to 0.3 (rounded 1/3) The point of solution seems close to one.