For each of the following, independent scenarios, indicate the nature of the costs as variable, fixed, mixed, or step costs.
1. A cellphone contract where there is a minimum cost per month plus additional cost for usage.
2. The depreciation cost of a machine that is calculated on a straight-line basis.
3. The delivery cost for a courier where the costs include wages of an employee, depreciation of the vehicle, and fuel costs.
4. The cost of a sales manager in a situation where one manager can supervise 10 salespeople.
5. The cost of reimbursing employees for the use of their automobiles where they are paid on the basis of the number of kilometres driven each month.
6. The depreciation cost of a machine where the depreciation is based on the units-of-production method.
7. The cost of a babysitter who charges $6 per hour.
8. The cost of leasing an automobile where the lessee is granted a certain number of kilometres during the lease, then is charged extra beyond the maximum allowable.