X Airlines provides the following direct flights: - Albany to Boston, Montreal, Orlando, Philadelphia, and San Francisco. - Boston to Albany, New York, and Montreal. - Montreal to Philadelphia and San Francisco. - New York to Orlando and San Francisco. - Orlando to San Francisco. - Philadelphia to Boston, Orlando, Montreal, and New York. - San Francisco to Philadelphia and Montreal. Based on this information, find the number of itineraries that exist for each of the following trips: (a) San Francisco to Philadelphia with at most 2 stops 1 (b) Boston to Orlando, with at most 3 stops (c) Orlando to Boston, with at most 4 stops