The right answer is the alternative D: a piece of land projecting into water .
The explanation for this is that in geography, a cape, promontory or point is a geographic accident formed by a mass of land that extends by an ocean or sea that is adjacent to it. A cable in general has more importance than a promontory, and often exerts influence on coastal currents and other oceanographic features of its environment. A cable, therefore, is a narrow peninsula.