单项选择题
SCENARIO 3.2: Lettuce and spinach are substitutes. Lettuce and tomatoes are complements. Lettuce is a normal good. During the winter, about 20% of the lettuce crop was destroyed by flooding.
Refer to Scenario 3.2. The government wants to protect consumers from rising food prices. Therefore, price restrictions are imposed on lettuce growers prohibiting them from raising the price of lettuce. This will cause
A．an excess demand for lettuce.
B．a decrease in the supply of lettuce.
C．an increase in the demand for lettuce.
D．an excess supply of lettuce.
