**Explanation:**

A cursor control device is a hardware device that allows users to move the cursor on a computer screen. It is used to navigate and control the movement of the cursor, which is typically represented as an arrow or other graphical element on the screen. The cursor control device provides a way for users to interact with the computer and perform various actions such as selecting, clicking, dragging, and scrolling.

Out of the options provided, the correct answer is option 'C' - Trackball. Here's why:

**Trackball**
A trackball is a cursor control device that consists of a ball that can be rotated in any direction. It is usually located on the top of the device and can be operated by the user's fingers or palm. The movement of the ball translates into the movement of the cursor on the screen. By rolling the ball in different directions, the user can control the position of the cursor and perform various actions. Trackballs are commonly used in computer mice, where the ball replaces the traditional mouse wheel.

**Printer**
A printer is a device that produces a physical copy of digital text or images on paper. It does not control the movement of the cursor and is not considered a cursor control device.

**Scanner**
A scanner is a device that captures and converts physical documents or images into digital formats. It does not control the movement of the cursor and is not considered a cursor control device.

**Microphone**
A microphone is a device that converts sound into an electrical signal. It is used for recording audio or inputting sound into a computer. It does not control the movement of the cursor and is not considered a cursor control device.

In conclusion, out of the given options, a trackball is the only device that functions as a cursor control device. It allows users to control the movement of the cursor on a computer screen by rotating a ball.