Money serves as ________

A grocery store shows the influence of competition when

a. no brands of peanut butter are on the store shelf b. one brand of peanut butter is on the store shelf c. two brands of peanut butter with the same price are on the store shelf d. two brands of peanut butter with different prices are on the store shelf

The cost to firms of changing prices

A) is called a menu cost. B) is small even when there is rapid inflation. C) does not exist if inflation is perfectly anticipated. D) all of the above