Which of the following graphs below represents the motion of an object at variable speeds?

A slanting straight line graph starting from a point on the y axis is shown with distance in miles on y axis and time in hours on x axis
A curved line graph starting from a point on the y axis is shown with distance in miles on y axis and time in hours on x axis
A straight line graph starting from the origin is shown with distance in miles on y axis and time in hours on x axis
A straight line graph parallel to the x axis is shown with distance in miles on y axis and time in hours on x axis