Which is more​ economical: purchasing the economy size of a detergent at 7 kilograms for ​$7.15 or purchasing the regular size at 920 grams for 60cents​?
Select the correct choice below and fill in the answer box to complete your choice.
​(Round to four decimal places as​ needed.)
A.
Purchasing the economy size is more economical because the economy size costs ​$
____ less per gram.
B.
Purchasing the regular size is more economical because the regular size costs ​$
_____ less per gram.