What should you do?

You are developing an application that has several automated builds that build, perform code analysis, and unit test portions of your code. Your team also performs peer review for code changes in an informal manner.
You need to meet the following requirements:
Provide documentation on quality checks and reviews for any changes to the code base.
Ensure code quality.
Maintain your team’s efficiency.
What should you do?
A. Institute gated check-ins to the build process.
B. Deny developers check-in permissions. Allow them to shelve changes and have a senior team member check in the shelve-set after review.
C. Utilize the Code Review work items and workflow before check-ins.
D. Perform a weekly code review on subset of recent check-ins.