Option A is the best answer because CHFI v11 explicitly includes Malware Analysis: Static and Dynamic and the use of a controlled malware analysis lab to examine suspicious files safely. The defining purpose of static analysis is to inspect a file without executing it , allowing the investigator to identify indicators such as strings, imports, headers, embedded resources, suspicious metadata, obfuscation, or other structural signs of malicious intent.
This is different from dynamic analysis , which involves running the file in a sandbox or controlled environment to observe behavior. Option B and C therefore describe dynamic analysis, not static analysis.
Option D may be part of deeper reverse engineering, but it is narrower and more advanced than the broader primary purpose of static analysis, which is safe, non-executing inspection to identify likely threats.
Because the question asks for the main reason to perform static analysis, the most accurate CHFI-aligned answer is analyzing the suspicious file's code and structure without running it in order to identify potential security threats.