The correct answers are C and D because they are the minimum requirements for deploying Apex code from a sandbox to production. According to the Salesforce documentation1, "To deploy Apex or package it for the AppExchange, at least 75% of your Apex code must be covered by unit tests, and all of those tests must complete successfully." Additionally, "Every test method must use the System.assert methods to verify that the expected behavior occurs." The other options are incorrect because they are not mandatory for deployment, but rather best practices or recommendations. Deploying during business hours may not be feasible or desirable for some organizations, depending on their availability and change management processes. Having at least one line of test coverage for each trigger is not enough to ensure code quality and functionality, and may not meet the 75% code coverage requirement. References:
* Apex Testing
* Deploy Apex
* Trailhead: Apex Testing