49. There are three kinds of book owners. _________(1) The second has a great many books, a few of which are read through. (2) The third has a few books, every one of which is well-read and marked from front to back. (3) However, all of these books are as clean and shiny as the day they were bought. (4) The first has all the standard sets and best-sellers, which are unread. (A) 1324 (B) 4213 (C) 4312 (D) 4132