Assume only the injurer can exercise precaution. Graph the expected social cost and the cost of precaution for (assume the cost of x units of precaution is $x). Put precaution on the horizontal axis and cost on the vertical axis. Clearly label the optimal level of precaution, the expected social cost curve, the cost of precaution, the permitted and forbidden zones, and show how the firm's expected cost is related to the two curves on the graph