1. In Question 4, suppose that the average price of meals purchased from restaurants had gone up from $12 to $13, while the average price of ingredients needed for meals prepared at home had remained at $5. When calculating the consumer price index for food in April 2020, the Bureau of Labor Statistics used the expenditure shares of meals prepared at home and at restaurants that it had calculated based on a household expenditure survey carried out in 2019 before the COVID-19 outbreak. The food price index calculated in this way,

1. a.is an accurate measure of the true cost of meals for American families.
2. b.underestimates the true cost of meals for American families.
3. c.overestimates of the true cost of meals for American families.
4. d.may underestimate or overestimate the true cost of meals for American families.