There are 40 match sticks in a match box. Sonia uses 3 match sticks every day. The fraction of match sticks she used in 7 days is:

• A. \[\frac{9}{40}\]               
• B. \[\frac{3}{40}\]
• C. \[\frac{1}{7}\]                  
• D. \[\frac{21}{40}\]