Answer:
B. col.
Step-by-step explanation:
A col is the lowest point (or dip) along an arête (a narrow ridge between two valleys), which serves as a pass from one side of a mountain range or ridge to another. A col is usually found between mountain peaks in a summit line, typically on a prominent ridge or arête. A col may also be referred to as a notch or a gap. An example of a col is the Indira Col on the Indira Ridge in Siachen Muztagh in the Karakoram Range.