In a Rectangular Coordinate System, the Magnitude of a Three-Dimensional

In a rectangular coordinate system, the magnitude of a three-dimensional vector obeys all of the following rules except

A) it is at least as large as that of any single component.
B) it is smaller than the simple arithmetic sum of the magnitudes of the components.
C) it is the square root of the sum of the squares of the individual components.
D) it may be positive or negative, depending on the direction of the components.