Answer:
The answer d. The workers are a variable input; the ovens are a fixed input.
Explanation:
Due to the nature of the lease (i.e. it being 10 months), it is not financially feasible to move to a location containing more ovens at this time. This means that the ovens are not variable. However, the workers are available on demand. Hence, he does not have to call all of them in every day. This means that they are variable, since he can use one to three workers at a time.