What is the correct description of the following DAX Iterator Function?

SUMX$($ Sales, Sales$[$Quantity$]*$ Sales$[$Price$])1)$ in the sales table, sum the quantity and price colums, then multiply the results. $2)$ in the data model, multiply the sum of quantity by the sum of price, and return the results for each row. $3)$ in the sales table, multiply the quantity and price columns for each row, then sum the results. $4)$ in the sales, multiply the sum of quantity by the sum of price, and return the results for each row