Determining what attack the odd characters are indicative of is the next step that should be taken after reviewing web server logs and noticing several entries with the same time stamps, but all contain odd characters in the request line. This step can help the analyst identify the type and severity of the attack, as well as the possible source and motive of the attacker. The odd characters in the request line may indicate that the attacker is trying to exploit a vulnerability or inject malicious code into the web server or application, such as SQL injection, cross-site scripting, buffer overflow, or command injection. The analyst can use tools and techniques such as log analysis, pattern matching, signature detection, or threat intelligence to determine what attack the odd characters are indicative of, and then proceed to the next steps of incident response, such as containment, eradication, recovery, and lessons learned. Official Reference:
https://partners.comptia.org/docs/default-source/resources/comptia-cysa-cs0-002-exam-objectives
https://www.comptia.org/certifications/cybersecurity-analyst
https://www.comptia.org/blog/the-new-comptia-cybersecurity-analyst-your-questions-answered

USB ports are a common attack vector that can be used to deliver malware, steal data, or compromise systems.
The first step to mitigate this vulnerability is to check the configurations of the company assets and disable or restrict the USB ports if possible. This will prevent unauthorized devices from being connected and reduce the attack surface. The other options are also important, but they are not the first priority in this scenario.
References:
CompTIA CySA+ CS0-003 Certification Study Guide, page 247
What are Attack Vectors: Definition & Vulnerabilities, section "How to secure attack vectors" Are there any attack vectors for a printer connected through USB in a Windows environment?, answer by user "schroeder"

According to the security policy, the company shall use the CVSSv3.1 Base Score Metrics to prioritize the remediation of security vulnerabilities. Option C has the highest CVSSv3.1 Base Score of 9.8, which indicates a critical severity level. The company shall also prioritize confidentiality of data over availability of systems and data, and option C has a high impact on confidentiality (C:H). Finally, the company shall prioritize patching of publicly available systems and services over patching of internally available systems, and option C affects a public-facing web server. Official References: https://www.first.org/cvss/