Answer:
A. what Mary can afford and what she cannot afford
Explanation:
The line will be the combination between Cookies and coffees she can afford with his daily income of 8
She can afford to purchase any combination on the line or below the line
for example,
She can buy either 4 coffees = 8
3 coffees 2 cookies = 8
2 coffee 4 cookies = 8
1 coffe 6 cookies = 8
8 cookies = 8
or just 1 coffe = 2
She cannot afford above the line
4 coffe and 3 cookies = 4*2 + 3 *1 = 11