Which sample of ocean water would be the most likely to have the highest salinity?
Ocean water taken from the surface of the ocean
The warmest sample of ocean water
The ocean water taken from an area near the polar ice caps
Ocean water taken from the bottom of the ocean

  Ocean water taken from the surface of the ocean

Explanation:

Attached is a plot of ocean salinity vs. depth. It shows the highest salinity ocean water is surface water. A world-wide map of ocean salinity shows the highest salinity to be in mid-latitude regions in the middle of the ocean. Water near the North Pole has lower salinity than that for lower latitudes.

Probably the main reason for higher salinity at the surface is the high evaporation rate of water there, leaving behind the salt.