The query that displays the Amount of loans $($LoanAmount$)$ by Year and by customer Sector $($CSector$)$ should use:

The SUM function and the clause $$ GROUP BY YEAR $$

The COUNT and $$GROUP BY YEAR, CSECTOR $$

The SUM function and the clause $$GROUP BY YEAR, CSECTOR $$

The SUM function and the clause $$ GROUP BY CSECTOR $$