Following is the part of overhead distribution line :

1. Conductor : It is the part which conducts electricity or transfer power from generating station to the consumer, many types of conductors are used in power transmission for example copper aluminium ACSR etc.

2. Insulators : Are used to isolate and protect the system from faults, earthing, from human beings etc.

3. Cross Arm  : To support the insulator and makes a ground of path.

A thimbles is not used in distribution line. It used in wiring diagram.

Hence, the correct option is (B).