The table below summarizes the number of books sold each day at a bookstore for 19 days:
| Number of books sold | Number of days |
|---|---|
| 1 to 5 | 3 |
| 6 to 10 | 5 |
| 11 to 15 | 4 |
| 16 to 20 | 5 |
| 21 to 25 | 2 |
Which of the following could be the median number of books sold in one day at this bookstore?
7
12
17
22
