$14.$ Klean Company experienced an accounting event that affected its financial statements as indicated below:

Assets $=$ Liab. $+$ Equity Rev.$/$Gain $$ Exp.$/$loss $=$ Net Inc. Cash Flow

$$ NA $$ NA $+$ FA

Which of the following events could have caused these effects?

a$.$ recognizing depreciation.

b$.$ paying cash for a capital expenditure.

c$.$ amortizing a patent.

d$.$ selling a long$-$term asset for a loss.