a$.$ Ava, age $19$ and single, has $$7,500$ of wages, $$750$ of interest, and $$250$ of self$-$employment income.

A$.$ Ava need not file because her gross income is less than the threshold of $$14,600$ and her self$-$employment income is less than $$400.$

B$.$ Ava need not file because her gross income is less than the threshold of $$14,600$ and her self$-$employment income is less than $$1,300.$

C$.$ Ava must file even though her gross income is less than the threshold of $$14,600$ because her self$-$employment income is greater than $$200.$

D$.$ Ava must file because her gross income exceeds the threshold of $$5,050.$