Which of the following is a common way to perform financial-statement analysis while searching for revenue-related analytical symptoms?

a. Look for unusual changes in revenue-related account balances from period to period (trends).
b. Look for unusual changes in revenue-related relationships from period to period.
c. Look for unusual changes in the cost of goods sold account from period to period.
d. Both a and b are common ways to perform within-statement analysis while searching for revenue-related analytical symptoms.
e. All of the above are common ways to perform financial-statement analysis while searching for revenue-related analytical symptoms.