One of the Many Steps in the Production of Toothpaste

One of the many steps in the production of toothpaste is to screw the caps on the tubes,which is still a manual process,performed by one man,Mr.Bucket.Which statement about this situation is BEST?

A) This is most appropriate for an output measure of capacity.
B) This is most appropriate for an input measure of capacity.
C) Utilization of the worker at this process step cannot be measures as it is a manual process.
D) In this case,the capacity of this step is not the maximum rate of output.