Final answer:
Stacy can make exactly 4 cards since she has 4 sheets of paper and each card requires one sheet. The correct model is division, which shows the number of cards per sheet.
Step-by-step explanation:
The student's question asks how many cards Stacy can make if she has 4 sheets of paper, and each card requires a sheet of paper. The answer to this question is straightforward, as it involves a one-to-one correspondence between the sheets of paper and the cards made. The appropriate model to solve this problem is option a. Model: Division; Explanation: Each sheet of paper corresponds to one card. This model is chosen because division represents how many times one number is contained within another, and in this case, how many cards can be 'contained' within the available sheets of paper. Since each card requires one sheet, it is a matter of dividing the total number of sheets (4) by the number of sheets required per card (1) to determine the total number of cards Stacy can make.