Chapter 9.4, Problem 9CV

If v is a vector with initial point $\left(x_1\text{,}{y}_1\right)$ and terminal point $\left(x_2\text{, }{y}_2\right)$, then which of the following is the position vector that equals v?

(a) $\langle x_2-x_1,y_2-y_1\rangle$

(b) $\langle x_1-x_2,y_1-y_2\rangle$

(c) $\langle \frac{x_2-x_1}{2},\frac{y_2-y_1}{2}\rangle$

(d) $\langle \frac{x_1+x_2}{2},\frac{y_1+y_2}{2}\rangle$