Sara and zoe are the only people in an economy. the following data tells you about their purchases of soda.
sara bought 3 bottles when the price is $3 a bottle, 4 bottles when the price is $2 a bottle, and 5 bottles when the price was $1 a bottle.
zoe bought no soda when the price was $3 a bottle, 2 bottles when the price is $2 a bottle, and 3 bottles when the price was $1 a bottle.
in the market for soda, the quantity demanded is

a. 4 bottles at $2
b. 5 bottles at $1
c. 5 bottles at $3
d. 6 bottles at $2