$6\mathrm{.}1.$ Which of the following statements is correct?

a$.$ Rate$-$of$-$return on equity indicates how efficient a company's management is at using its assets to generate earnings.

b$.$ The Current Ratio is part of the category of ratios known as "Profitability Ratios".

c$.$ A common$-$size balance sheet represents two or more years of balance sheets relative to a base year.

d$.$ A journal entry to record receiving cash for the sale of farm products includes a debit to the Cash account.