35+67-12x3+78= c(ha)t or (fr)ee p(oin)ts? Which one answers it?

Two technicians are discussing oil changes. technician a says that waste oil and old filters need to be disposed of according to the law. technician b says that old filters can be returned to the parts department for a core value. which technician is correct?           a. technician a only   b. both technicians a and b   c. technician b only   d. neither technician a nor b