Assume That a Consumer Can Spend $20 on Two Goods-Pens

Assume that a consumer can spend $20 on two goods-pens and pencils.If the price of one pen is $5 and the price of one pencil is $2,which of the following combinations of the two goods represents a point on the consumer's budget constraint?

A) 3 pens and 2 pencils
B) 1 pen and 10 pencils
C) 2 pens and 5 pencils
D) 2 pens and 3 pencils