*30 POINTS + BRAINLIEST ANSWER*
Gravity is pulling an object into the sun. The closer the object gets to the sun, the greater the gravitational force that acts on the object, increasing its acceleration. A line graph plotting the speed of the object against time would have which shape?
A: straight line of positive slope
B: curved line that slopes upward
C: curved line that slopes downward
D: straight line of negative slope