A government wants to raise steel production and expand steel sales by providing subsidies to private producers. A subsidy of $W - Z per tonne is given. Using the diagram, what would the sales value of steel be after the subsidy?
- A$OP \times OQ$
- B$OP_1 \times OQ_1$
- C$WZ \times OQ$
- D$WZ \times OQ_1$