单选题

The diagram to the below illustrates a consumer's allocation of her budget between items X and Y. With an initial budget (BC₁ ) she consumes Q_a units of item Y. When the price of Y drops, she consumes Q_c units of item Y. Lines BC₂ and BC₃ are parallel to one another.

A、
Q_b and Q_a .
B、
Q_c and Q_a .
C、
Q_c and Q_b .

【正确答案】 C

【答案解析】

When the price of Yfalls, the budget constraint shifts outward from BC₁ to BC₂ , indicatingan increase in the consumption of X Points a and b reflect the change in consumption of Ydue solely to a decrease in price because BC₃ reduces her income by a sufficient amount to return her to her original indifference curve. Q_c - Q_b is the income effect (which is negative here) because it is an inferior good.