Which substance will cool down the slowest during the night, and why?

A) Seawater, because it heats up faster but gives away heat slower than sand.
B) Seawater, because it heats up slower and gives away heat slower than sand.
C) Sand on the shore, because it heats up faster but gives away heat slower than water.
D) Sand on the shore, because it heats up faster and gives away heat faster than water.