The correct regular expression to match a GET request to this API endpoint is " https://10\.1\.2\.3/api\?id=\d+
" . This pattern checks for the specific URL with an id parameter that accepts integer values. The syntax \d+ matches one or more digits, which aligns with the requirement for a single integer argument. Other options either use incorrect syntax or do not accurately capture the expected URL format. Regular expressions are vital in filtering and identifying patterns in logs, as recommended by CompTIA Cybersecurity Analyst (CySA+) practices for threat hunting and log analysis.