Authentication is a method of verifying a user's identity by requiring some piece of evidence, such as something the user knows (e.g., password), something the user has (e.g., token), or something the user is (e.g., fingerprint). Authentication is the best method to prevent unauthorized use of an API, because it ensures that only legitimate users can access or use the API functions or data. HTTPS, geofencing, or rate limiting are other methods that can enhance the security or performance of an API, but they do not prevent unauthorized use of an API. Reference: https://www.redhat.com/en/topics/api/what-is-api-security

Reporting processes are important to include when updating an incident response plan after a breach for several reasons. Two of the most likely reasons are:
To meet regulatory requirements for timely reporting. Many regulations and standards require organizations to report security incidents or breaches within a certain time frame or face penalties or sanctions. For example, the General Data Protection Regulation (GDPR) requires organizations to report personal data breaches within 72 hours of becoming aware of them. Reporting processes can help organizations to comply with these requirements by defining who, what, when, where, how, and why to report incidents or breaches.
To limit reputation damage caused by the breach. Security incidents or breaches can have negative impacts on an organization's reputation, trust, and customer loyalty. Reporting processes can help organizations to limit these impacts by communicating effectively and transparently with internal and external stakeholders, such as employees, customers, partners, regulators, media, and public. Reporting processes can help organizations to provide accurate and consistent information about the breach, its causes, impacts, and remediation actions.
Other possible reasons to include reporting processes when updating an incident response plan after a breach are:
To establish a clear chain of command (A). Reporting processes can help organizations to establish a clear chain of command for incident response by defining roles and responsibilities, escalation procedures, and decision-making authority.
To remediate vulnerabilities that led to the breach (D). Reporting processes can help organizations to remediate vulnerabilities that led to the breach by documenting and analyzing the root causes, lessons learned, and best practices for improvement.
To isolate potential insider threats (E). Reporting processes can help organizations to isolate potential insider threats by monitoring and auditing user activities, behaviors, and access rights before, during, and after the breach.

Blocking the download of the file via the web proxy is the best change to make to the security tools to remedy the issue. A web proxy is a server that acts as an intermediary between a client and a web server, filtering or modifying requests and responses according to predefined rules1. Blocking the download of the file via the web proxy can prevent developers from accessing and executing the offending file that is bundled with adware. This can reduce the risk of infection or compromise of the developer workstations and improve their performance and security. Blacklisting the hash in the next-generation antivirus system (A) is not the best change to make to the security tools to remedy the issue. Blacklisting is a technique that involves blocking or denying access to known malicious or unwanted entities based on their identifiers, such as hashes, IP addresses, domains, etc2. Blacklisting the hash in the next-generation antivirus system can prevent developers from executing the offending file that is bundled with adware, but it does not prevent them from downloading it. This can still consume network bandwidth and disk space and expose developers to potential threats. Manually deleting the file from each of the workstations (B) is not the best change to make to the security tools to remedy the issue. Manually deleting the file from each of the workstations can remove the offending file that is bundled with adware, but it does not prevent developers from downloading it again. This can be a time-consuming and inefficient process that requires human intervention and coordination. Removing administrative rights from all developer workstations is not the best change to make to the security tools to remedy the issue. Removing administrative rights from all developer workstations can limit developers' ability to install or execute unauthorized or malicious applications, such as adware, but it does not prevent them from downloading them. This can also affect developers' productivity and functionality by restricting their access to legitimate applications or settings.

data exfiltration is the unauthorized transfer of data from an organization's network to an external destination, usually for malicious purposes such as espionage, sabotage, or theft. The details given in the question suggest that data exfiltration is occurring from an endpoint device. The bursts of network utilization every seven days indicate periodic data transfers. The content being transferred appears to be encrypted or obfuscated to avoid detection or analysis. The persistent outbound TCP connection from the host to infrastructure in a third-party cloud indicates a possible command and control channel for an attacker. The HDD utilization on the device grows by 10GB to 12GB over the course of every seven days, and single file sizes are 10GB, indicating that large amounts of data are being collected and compressed before being exfiltrated.

This is most likely occurring based on the symptoms observed after a recent sales meeting. An insider threat is a person who has legitimate access to an organization's network or data and uses it for malicious purposes, such as stealing, leaking, or sabotaging information. The symptoms suggest that someone from the sales team or someone who attended the meeting has copied sensitive corporate documents and uploaded them to the dark web using large data packets.