A regional manager records the number of customers served on one Monday at each of the seven coffee shops in a chain, as shown in the table.
| Shop | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|
| Customers served | 88 | 94 | 101 | 107 | 112 | 119 | 126 |
Which of the following is the interquartile range of the numbers of customers served?