Direction: David and Dravid started from a place denoted by 0, in opposite directions. After Dravid walked for 8 m, he met Sajid. After 7 m from the starting point David met Sahid. Dravid went back 2 m to buy a book. David went ahead 3 m to the library. At which point did Dravid buy the book?

• A. A                           
• B. C  
• C. O                           
• D. B