The littoral zone is the region where the land meets a body of water, and although the exact definition can vary, it generally includes land that is always dry and a region that is always submerged. A and B more or less say the same thing, and both describe the littoral zone. It almost always features vegetation (think of plants growing out of marshes and near/in the shore of rivers and lakes). It stabilizes the soil by providing a more gradual transition from land to water. For example, an area that only the high tide of the sea reaches will feature some chemical composition of the sea bed, such as more water and salinity, and some of the land further inland.
