Final answer:
In the context of reservation data, (b) means of travel or transportation and (c) type of sleeping accommodations requested fall into the non-essential category, while (a) name & number in party and (e) date of arrival are essential.
Step-by-step explanation:
In the context of reservation data, the non-essential or nice-to-know category refers to information that is not necessary for completing a reservation but provides additional details about the reservation. From the options given, (b) means of travel or transportation and (c) type of sleeping accommodations requested fall into the non-essential category because they provide extra information that may be helpful but are not required to complete the reservation. On the other hand, (a) name & number in party and (e) date of arrival are essential or need-to-know data as they are crucial for making the reservation.