A Block of Ice Slides Freely [No Air Resistance, No

A block of ice slides freely [no air resistance, no friction] down a slippery slope. The block starts from rest at the top of the slope, where it has a vertical height of 4 m above the bottom of the slope and where it has a gravitational energy of 1000 J. The block's total energy a quarter of the way down the slope [at a height of 3 m] is

A) 250 J.
B) 500 J.
C) 750 J.
D) 1000 J.
E) greater than 1000 J.