If the point (1,4) is on the graph of an equation, which statement must me true? a) the values x=1 and y=4 make the equation true. b) the values x=4 and y=1 make the equation true. c) the values x=1 and y=4 are the only values that make the equation true. d) there are solutions to the equation for the values x=1 and x=4.