Laura was in charge of purchasing food for the next book club meeting. She usually ordered sandwiches from the nearby deli, but the price of sandwiches had increased. One option for food was ordering pizza, which was $3 less than a sandwich. However, because the price of sandwiches had gone up, Laura could afford fewer sandwiches and pizza than previous meetings. The reduction in Laura's ability to purchase both sandwiches and pizza due to the increase of price in sandwiches is known in economic terms as . a budget constraint the substitution effect the income effect a change in income