(Table) Based on the Table, at What Wage Rate Is

Multiple Choice

(Table) Based on the table, at what wage rate is the supply curve backward bending?
$\begin{array}{c}\text { Labor Supply Schedule }\\\begin{array}{|c|c|}\hline \text { Wage Rate (S/hr.) } & \text { Hours of Work (per week) } \\\hline 20 & 30 \\\hline 30 & 40 \\\hline 40 & 50 \\\hline 50 & 40 \\\hline 60 & 30 \\\hline\end{array}\end{array}$

A) after $20 per hour
B) after $30 per hour
C) after $40 per hour
D) after $50 per hour