Which of the Following Should Be Attempted in Order to Gauge

Which of the following should be attempted in order to gauge the quality of a company's earnings?
I. Assess adequacy of discretionary expenditures
II. Assessing degree of conservatism in reporting assets
III. Assessing degree of conservatism in reporting liabilities
IV. Assessing degree of conservatism in application of accounting principles

A) I, II, III and IV
B) I, II and IV
C) II, III and IV
D) I, III and IV