When overriding standard buttons in Salesforce Classic and Lightning Experience, different technologies are used.
Salesforce Classic:
Visualforce pages are used to override standard buttons like Edit.
Lightning Experience:
Lightning Components (Aura Components or Lightning Web Components) are used.
Option C: A Visualforce page in Salesforce Classic and a Lightning component in Lightning Experience Correct Answer.
In Salesforce Classic, override the Edit button with a Visualforce page.
In Lightning Experience, use a Lightning Component to override the Edit action.
Reference:
Overriding Standard Buttons
Overrides in Lightning Experience
Options Not Applicable:
Option A and B: Lightning components cannot be used in Salesforce Classic.
Option D: A Lightning page cannot be used to override standard buttons.
Conclusion:
The developer should use a Visualforce page in Salesforce Classic and a Lightning component in Lightning Experience, which is Option C.

For integrating automated tests into a Continuous Integration (CI) process, the Universal Containers development team should use the Salesforce CLI.
Option C: Salesforce CLI
Automated Testing:
Developers can use the sfdx force:apex:test:run command to run Apex tests and include it in their CI scripts.
Example Command:
sfdx force:apex:test:run --testlevel RunLocalTests --resultformat human --outputdir test-results Reference:
"Use Salesforce CLI to automate your development and build CI/CD pipelines."
- Salesforce CLI Command Reference
Why Other Options Are Incorrect:
Option A: Developer Console
The Developer Console is a web-based tool within Salesforce for development but is not suitable for automating tests in a CI process.
Option B: Visual Studio Code
While VS Code with Salesforce extensions is a powerful IDE, it is not a CI tool itself. It can be used to develop code but not to automate tests as part of a CI pipeline.
Option D: Force.com Toolkit
The Force.com Toolkit is outdated and does not provide the necessary functionality for modern CI processes.
Conclusion:
Salesforce CLI is the appropriate tool for integrating automated testing into a CI pipeline, allowing developers to script test runs and integrate with CI servers.

Fast field updates record-triggered flow and account trigger are two automation tools that can be used to implement the feature of updating the Timezone field based on the postal code. A fast field update is a type of flow action that can update one or more fields on a record without using any Apex code1. A record-triggered flow can be configured to run when a record is created or updated, and can perform actions such as fast field updates, invocable actions, or subflows2. An account trigger is a piece of Apex code that can execute before or after an account record is inserted, updated, deleted, or undeleted, and can perform complex logic or callouts to external services3. Both of these tools can access the PostalCodeToTimezone_c custom object and update the Timezone field accordingly. References:
* Fast Field Updates, Trailhead module
* Record-Triggered Automation, Trailhead module
* Apex Triggers, Trailhead module