I'm struggling to calculate these practice questions could you help?

In this problem, we use the economic model of fisheries to analyse changes in the model parameters.

Figure 12.4 Efficient Sustainable Yield for a Fishery

Source: Tietenberg & Lewis, (2014), Figure 12.4 on p. 283

Using Figure 12.4, answer the following questions:

a. What is the level of effort that achieves the maximum sustainable yield? Explain.

b. What is the level of effort that achieves the efficient sustainable yield? Explain

c. What is the level of effort that is associated with the unregulated open access fishery? Explain

d. If there were a reduction in the cost of fishing, how would this affect the efficient sustainable yield? How would this affect effort in an open access fishery? Why?

FIGURE 14.2 Efficient Sustainable Yield for a Fishery Benefits and Costs of Fishing Effort (dollars) Tangent Total Costs, Benefits C(E.).... Quantity of Fishing 0 Ee Em Effort (units)