In order to promote off-season business, Mt. Dunmore Lodge made the following "Welcome Back" offer to their winter guests: guests who rent a room for at least a week during ski season can come back during the summer and get 25% off the standard summer price of any room they rent. After the summer passed, the owners of the lodge determined that the majority of their guests had taken advantage of the "Welcome Back" offer and paid the reduced rates. However, they were surprised to find they still managed to rent more rooms at full price than they did at the discount rate.
Which of the following, if true, most helps to explain the apparent discrepancy in the passage?

(A) Most of the guests who stayed at Mt. Dunmore Lodge during the winter did not stay for a full week.
(B) Those guests taking advantage of the "Welcome Back" discount were more likely to bring their families with them than were those guests who were paying full price.
(C) Some of the guests who received the "Welcome Back" discount also received a 10% rate reduction through their auto club.
(D) In order to pay for the construction of a new gymnasium and a new pool, the owners of the lodge raised their summer prices considerably.
(E) On average, guests who took advantage of the "Welcome Back" discount spent more money at the hotel on additional goods and services than guests who paid full price for their rooms.

OA B . I did not understand the official explanation. Any thoughts?