Identify the accounting concept or principle (there may be more than one) that gives the most direction on how to account for each of the following situations:

a. The owner of a business desires monthly financial statements to measure the progress of the entity on an ongoing basis.

b. Expenses of the period total $5,500. This amount should be subtracted from revenue to compute the period's net income.

c. Expenses of $1,200 must be accrued in order to measure net income properly.

d. A customer states her intention to switch health clubs. Should the new health club record revenue based on this intention? Give the reason for your answer.