Each shelf of a bookcase contained 12 books. If the librarian took out 21 books and rearranged the remaining books so that all shelves but the last one contained 8 books and that last shelf contained 11 books, how many shelves does the bookcase have?
A. 5
B. 6
C. 7
D. 8
E. 9
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A. 5
B. 6
C. 7
D. 8
E. 9
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