ANS:B - Stud

The fastening device that has both ends threaded is called a "Stud." A stud is a type of fastener that has threads on both ends. One end is typically threaded into a component or a structure, while the other end is used to secure another component with a nut. Studs are often used in applications where the fastening needs to be removable or where a more secure and precise fastening method is required compared to bolts. So, the correct option is: Stud