Explanation:

Debugging is the systematic process of identifying, analyzing, and removing errors or 'bugs' from computer software. It involves examining the code, tracing its execution, and using specialized tools to pinpoint the source of unexpected behavior or incorrect results. Option (a) 'Compiling' is the process of translating source code written in a high-level programming language into machine code. Option (b) 'Testing' is the broader process of evaluating software to find bugs and ensure it meets requirements, but 'debugging' specifically refers to the act of searching for and fixing those bugs. Option (c) 'Running' simply means executing the software. Therefore, (d) 'Debugging' is the most accurate description of the process of searching for and resolving bugs.