Which of the following is true about this SQL program?

SELECT line.Inv_Number AS InvNumber,

SUM(line.Line_Units*line.Line_Price) AS InvoiceTotal

FROM invoice, line

WHERE invoice.Inv_Number = line.Inv_Number

GROUP BY line.Inv_Number;

Select one:

a. It uses an aggregate function.

b. It joins two tables but the join condition is incorrect.

c. It displays a value every time the invoice number changes.

d. a., b., and c.

e. a. and c. only.

It is not looking for values, its looking on the answer based on the syntax code provided