Abe is buying wrapping paper and shopping for the best deal. drag the rolls of wrapping paper in order from the least to the greatest unit cost in dollars per square foot.

So you need to compute all the rates to see which is the best deal.

$1.79/12.5ft^2=$0.1432 per ft^2

$5.29/40ft^2=$0.13225 per ft^2

$8.49/50ft^2=$0.1698 per ft^2

$6/60ft^2=$0.10 per ft^2

So the last option is the cheapes per square foot and thus is the best deal.  Ordered from least to greatest.

Sherbert, blue, red, and green