What are the signs of the torques caused by forces 1, 2, 3, and 4, respectively, about the origin of the coordinate system shown in Figure 7.27c?
$$
\begin{array}{ll}{\text { (a) }+,+,+,+} & {\text { (b) }-,+,-, 0} \\ {(\mathrm{c})+,-,+, 0} & {\text { (d) }-,-,-, 0} \\ {\text { (e) }+,-,+,} & {\text { (d) }-,-,-, 0}\end{array}
$$