Costing methods

Hi guys

Could anybody explain to me why question (iii) is None of these costing method?

Consider the following features and identify whether they relate to job costing, contract costing, service costing or none of these costing methods.

J = Job costing
C = Contract costing
S = Service costing
N = None of these costing methods

(i) Production is carried out in accordance with the wishes of the customer.

(ii) Work is usually of a relatively long duration.

(iii) Work is usually undertaken on the contractor’s premises.

(iv) Costs are averaged over the units produced in the period.

(v) It establishes the costs of services rendered.

Thanks alot