Answer: b. actuator
Explanation:
We know that a RW head ( or also known as read/write head) is a component of device which is usually appeared on the hard drive which is used to read and write data by the hard drive's disk . When data required to be read or write, the read/write arm is regulated by actuator.
[An actuator is a part of a device that is mainly responsible for moving and controlling a mechanism or system.]
Hence, All the read/write heads a hard disk are controlled by an actuator .
