(a) There are 17" appetizers available at a restaurant. From these, Maria is to choose 13 for her party. Howr many groups of 13 appetizers are possible? [D {b} There are 13 European cities that Maria would eventually like to visit. On her next vacation, though, she only has time to visit 3 of the cities: one on Monday, one on Tuesday, and one on wednesdav. She is now trying to make a schedule of which city she'll visit on which day. How many different schedules are possible? [Assume that she will not visit a city more than once.) E