Chapter 3, Problem 3.3QQ

If vector $\stackrel{\to }{B}$ is added to vector $\stackrel{\to }{A}$, which two of the following choices must be true for the resultant vector to be equal to zero? (a) $\stackrel{\to }{A}$ and $\stackrel{\to }{B}$ are parallel and in the same direction. (b) $\stackrel{\to }{A}$ and $\stackrel{\to }{B}$ are parallel and in opposite directions. (c) $\stackrel{\to }{A}$ and $\stackrel{\to }{B}$ have the same magnitude. (d) $\stackrel{\to }{A}$ and $\stackrel{\to }{B}$ are perpendicular.