Implement multi-factor authentication (MFA) and end-to-end encryption for all email communications, without considering additional security features due to budget constraints.

Specify comprehensive security requirements for the email service, including advanced email filtering, spam and phishing protection, data loss prevention (DLP), and compliance with industry standards, ensuring the solution is scalable and cost-effective.

Focus solely on securing the network infrastructure and endpoints used to access the email service, assuming the cloud provider's security measures are sufficient for email protection.

Rely exclusively on the email service provider's built-in security features, without implementing any additional security controls, to minimize costs and simplify management.