A government wants to raise output and expand steel sales by giving subsidies to private producers. Each tonne receives a subsidy of $W - Z$. Using the diagram, what is the value of sales of steel after the subsidy?
- A$OP \times OQ$
- B$OP_1 \times OQ_1$
- C$WZ \times OQ$
- D$WZ \times OQ_1$