Jane has £500 a week to spend on food and clothing. The price of food is £10 and the price of clothing is £25. Which of the following pairs of food and clothing are in Jane's choice set?
a) 10 units of clothing and 25 units of food.
b) 20 units of clothing and 50 units of food.
c) 0 units of clothing and 500 units of food.
d) 50 units of clothing and 50 units of food.