Let ${\bf u}$ and ${\bf v}$ be vectors in a Euclidean space.

Select the best statement.

A. The difference ${\bf u}-{\bf v}$ is found by adding ${\bf u}$ to ${\bf v}$.
B. The difference ${\bf u}-{\bf v}$ may not be defined.
C. The difference ${\bf u}-{\bf v}$ is found by adding $-{\bf u}$ to $-{\bf v}$.
D. The difference ${\bf u}-{\bf v}$ is found by adding ${\bf u}$ to${\bf -v}$.
E. The difference ${\bf u}-{\bf v}$ cannot be computed by a simple formula.
F. none of the above