Problem management is an IT service management activity that is most likely to help with identifying the root cause of repeated instances of network latency. Problem management involves analyzing incidents that affect IT services and finding solutions to prevent them from recurring or minimize their impact. Change management is an IT service management activity that involves controlling and documenting any modifications to IT services or infrastructure. Incident management is an IT service management activity that involves restoring normal service operation as quickly as possible after an incident has occurred.
Configuration management is an IT service management activity that involves identifying and maintaining records of IT assets and their relationships. References: ISACA, CISA Review Manual, 27th Edition, 2018, page 334

Access to production source and object programs is the best way to ensure that effective change management is in place in an IS environment, as it prevents unauthorized or accidental changes to the production code that could affect the functionality, performance, or security of the system. Access to production source and object programs should be restricted to authorized personnel only, and any changes should follow a formal change management process that includes documentation, approval, testing, and review.
References
ISACA CISA Review Manual, 27th Edition, page 254
Change Management Best Practices for the Engineering and ...
Change Management - an overview | ScienceDirect Topics

Digital watermarks are hidden marks or codes that can be embedded into digital files, such as images, videos, audio, or documents. They can be used to identify the source, owner, or authorized user of the data, as well as to track any unauthorized copying or distribution of the data. Digital watermarks can help prevent data leakage by deterring potential leakers from sharing sensitive data or by providing evidence of data leakage if it occurs.
The other options are not as effective as digital watermarks in preventing data leakage. Ensuring that paper documents are disposed securely can reduce the risk of physical data leakage, but it does not address the digital data leakage that is more prevalent in today's environment. Implementing an intrusion detection system (IDS) can help detect and respond to cyberattacks that may cause data leakage, but it does not prevent data leakage from insiders or authorized users who have legitimate access to the data. Verifying that application logs capture any changes made can help audit and investigate data leakage incidents, but it does not prevent them from happening in the first place.
References:
* What is Data Leakage?
* What is Digital Watermarking?