Which law of motion accounts for the following statement?"The gravity of the Sun causes the planets to move in a circular path."
The law that accounts for that exact statement is the law that says that
most people don't understand these things very well.
A better statement is:
"The gravitational forces between the Sun and each planet cause each planet
to move in an elliptical path."
The laws that account for that behavior are:
-- Newton's second law of motion: (Force) = (mass) x (acceleration)
-- Newton's law of universal gravity