Answer:
c. screw
Step-by-step explanation:
A screw can be descried as kind of fastener that is usually made of metal with helical thread around it and a slotted head which is used to fasten things together in order to hold it tightly in a place.
The function of a screw in a pair of scissors is to fasten each of the two parts together and hold them tightly together in place as a pair.
Therefore, the correct option is c. screw.