Mr. Chen goes to the post office to buy small and large boxes. He needs at least 4 small boxes. Altogether, he will buy no more than 15 boxes. The post office has 10 small boxes and 9 large boxes in stock. The graph shows the feasible region, where x represents the number of small boxes and y represents the number of large boxes. Which ordered pairs meet all the constraints and make sense in context of the situation? Select each correct answer. (6, 9) (7,10) (8,6) (9,8) Graph of lines and a shaded region on a coordinate plane whose axes are labeled x and y. A solid vertical line passes through 4 comma 0. Another solid vertical line passes through 10 comma 0. A solid horizontal line passes through 9 comma 0. A solid diagonal line passes through 0 comma 15, 4 comma 11, 6 comma 9, and 10 comma 5. The polygon whose vertices are at 4 comma 9, 6 comma 9, 10 comma 5, 10 comma 0, and 4 comma 0 is shaded.