Valerie wants to implement an email security framework that will help to ensure that only authorized systems send email on behalf of her domains. Which of the following should she implement?

The Sender Policy Framework (SPF) lists IP addresses of systems allowed to send email in DNS TXT records for a domain. DKIM (DomainKeys Identified Mail) validates a domain’s identity using a public key pair, validating the authenticity of the sender. DMARC (domain- based message authentication, reporting, and conformance) controls how unauthenticated messages are handled by mailbox providers, including quarantining, rejecting, or rejecting messages. STP is not an email security framework.