The triangular region shows the number of possible red thumbtacks, x, and the number of possible blue thumbtacks, y, that are placed on a bulletin board. the ordered pairs represent possible combinations of red thumbtacks and blue thumbtacks that can be placed on the bulletin board. which ordered pairs make sense in the context of the situation? select each correct answer. a- (2,3) b-(4,7.5) c-(7,4) d-(3,2) e-(7.5,5)