Concept:Isohalines are lines on maps that connect places in the ocean with equal salinity.Explanation:Salinity measures the amount of dissolved salt in seawater.A line drawn through points that have the same salinity value is called an isohaline.This term comes from “iso” meaning equal and “haline” referring to salt.Isobars, by contrast, connect points of equal atmospheric pressure.Therefore, the correct option is the one that means equal salt content.Answer:A. isohalines