The correct answer is B. This option meets the firm's requirements by creating a new S3 bucket with versioning enabled to keep track of any changes to the files. Additionally, S3 Object Lock with a retention period ensures that the files cannot be deleted or modified until the specified future date. Configuring the bucket for static website hosting ensures the files are publicly readable, while the bucket policy enforces read-only access. This configuration guarantees both security and accessibility, making it the most secure solution.