A. Store frequently used data and instructions for quick access
B. Perform arithmetic operations
C. Manage power supply to the CPU
D. Control input/output devices

Solution

A. Store frequently used data and instructions for quick access

Explanation

<p><span style="font-size: 14px;">Registers in a CPU are small, high-speed memory locations that <b>store frequently used data and instructions for quick access,</b> reducing the need to fetch them from slower main memory (RAM). This improves processing speed and efficiency.</span></p>