Answer:
Rosa is correct in using a division expression because the term "per" implies the quotient of the quantities before and after that word.
Explanation:
Given that
1 pound of ground beef sells for $4.
To find the cost per pound:
We need to divide the cost with the number of pounds.
i.e.

If 'Number of pounds' = 1, then cost per pound = Total Cost
Therefore, the above division expression can be used to find the Cost pound.
Putting the values given to find the 'Cost per pound':

Therefore, Rosa's belief is correct that, a division expression can be used.
The correct answer is:
Rosa is correct in using a division expression because the term "per" implies the quotient of the quantities before and after that word.