| List I | List II |
|---|---|
| A. Proprietary statements | I. Legal rules followed in operation of business |
| B. Franchising | II. Type of relationship |
| C. Contract explanation | III. Use of name |
| D. Operation manual | IV. Gives exclusive rights of local distribution to independent retailers |
What comes next in the series?
\(2, 6, 12, 20, 30, \ ?\)