The following details relate t

The following details relate to three services provided by RST Company: All three services use the same type of direct labour which is paid $25 per hour. The fixed overheads are general fixed overheads that have been absorbed on the basis of machine hours. What are the most and least profitable uses of direct labour, a scarce resource?
A、Most profitable S Least profitable R
B、Most profitable S Least profitable T
C、Most profitable T Least profitable R
D、Most profitable T Least profitable S