Which of the following determines the master or slave in a system that supports two IDE devices?

A.
A twist in the cable.

B.
The device that was installed first.

C.
The jumper settings.

D.
The BIOS.

Explanation:
You implement the master/slave setting by jumpering a set of pins.
Incorrect Answers:
A: Determines the drive letter for Floppy drives.
B: When you install a second drive, you have to configure it so that the controller on one drive is active and the other drives use the controller on this drive for their instructions.
D: The BIOS come into play only after configuring the devices as master/slave.
Reference:
David Groth and Dan Newland, A+ Complete Study Guide (2nd Edition), Sybex, Alameda, CA, 2001, pp. 170, 174, 175, and 176.