A Block of Mass M Starts from Position 1 and Moves

Multiple Choice

A block of mass m starts from position 1 and moves up a frictionless inclined plane with an initial speed v. At some later time the block has moved down the plane and at position 2 has a speed u. If a and b are the heights above the bottom of the plane, the magnitude of u can be determined from

A) u² = v² - 2g(a - b)
B) u² = v² + 2g(a + b)
C) u² = v² + 2g(a - b)
D) u² = v² + 2g(b - a)
E) u² = v² + g(a - b)