Which of the following could be used to calculate the profit for a firm?

The basic premise behind worker trade-offs in a market economy is that:

A. workers decide how to allocate their time between work and leisure. B. workers don't decide how much leisure to have. The amount of leisure depends on the number of hours they must work, which is determined by the firm. C. the trade-off between work and leisure is determined by factors other than what workers or firms would determine to be optimal. D. firms decide how much workers must work and workers decide how much leisure to have.

Refer to the figure above. The producer surplus before the imposition of the tax is given by the area ________

A) GHF B) GAE C) JBHF D) JBC