The explanation given in the manual is:
The information security manager's knowledge of the business is the most critical factor for information security program success because it enables him or her to align security objectives with business goals and communicate effectively with senior management and other stakeholders. The other choices are important elements of an information security program but not as critical as the information security manager's knowledge of the business.
An information security program is a set of policies, procedures, standards, guidelines, and tools that aim to protect an organization's information assets from threats and ensure compliance with laws and regulations.
An information security manager is a professional who oversees and coordinates the implementation and maintenance of an information security program. An information security manager should have a good understanding of the business environment, culture, strategy, processes, and needs of an organization to ensure that security supports its objectives.

= Proactive systems monitoring is the best method to protect against emerging APT actors because it can help detect and respond to anomalous or malicious activities on the network, such as unauthorized access, data exfiltration, malware infection, or command and control communication. Proactive systems monitoring can also help identify the source, scope, and impact of an APT attack, as well as provide evidence for forensic analysis and remediation. Proactive systems monitoring can include tools such as intrusion detection and prevention systems (IDPS), security information and event management (SIEM) systems, network traffic analysis, endpoint detection and response (EDR), and threat intelligence feeds.
References = CISM Review Manual 15th Edition, page 201-2021; CISM Practice Quiz, question 922

Positioning security as a business enabler is the BEST way to obtain organization-wide support for an information security program, because it helps to demonstrate the value and benefits of security to the organization's strategic objectives, performance, and reputation. By aligning security with the business goals and needs, the information security manager can gain the buy-in and commitment of senior management and other stakeholders, and foster a positive security culture across the organization.
References =
CISM Review Manual, 16th Edition, ISACA, 2020, p. 37: "The information security manager should position information security as a business enabler that supports the achievement of the enterprise's business objectives and adds value to the enterprise." CISM Review Manual, 16th Edition, ISACA, 2020, p. 39: "The information security manager should communicate the value and benefits of information security to senior management and other stakeholders to obtain their support and commitment for the information security program." CISM Review Manual, 16th Edition, ISACA, 2020, p. 40: "The information security manager should promote a positive security culture within the enterprise by influencing the behavior and attitude of employees and other parties toward information security."

According to the CISM Review Manual, one of the best ways to contain an SQL injection attack that has been detected by a web application firewall is to reconfigure the web application firewall to block the attack.
This means that the web application firewall should be updated with the latest detection patterns and rules that can identify and prevent SQL injection attacks. By doing so, the web application firewall can reduce the impact and damage of the attack, and prevent further exploitation of the vulnerable database1 The other options are not as effective as reconfiguring the web application firewall to block the attack. Force password changes on the SQL database is a reactive measure that does not address the root cause of the problem, and may cause data loss or corruption if not done properly. Updating the detection patterns on the web application firewall is a preventive measure that can help to detect SQL injection attacks, but it does not stop them from happening in the first place. Blocking IPs from where the attack originates is a defensive measure that can limit or stop some SQL injection attacks, but it does not protect all possible sources of malicious traffic, and may also affect legitimate users or applications1 References = 1: CISM Review Manual, 16th Edition, ISACA, 2020, pp. 32-33...