Which of the Following Explanations Were Given by O'Connor for the Increased

Which of the following explanations were given by O'Connor for the increased consumer perception that on-line reservations offer lower room rates compared to other distribution channels?

A) Many of the best-known internet retailers i.e., Amazon.com) initially competed with traditional outlets based on price.
B) Consumers are aware that web-based distribution costs are lower than those of other channels.
C) Many hotels use the web site to sell last-minute deals at relatively low prices but with short lead times.
D) All of the above
E) Only a and b