Which of the following is a feature of outbound integration security in Salesforce?

Two-way SSL, also known as mutual SSL, is a feature of outbound integration security in Salesforce that ensures both the client and the server authenticate each other. This is crucial for establishing a secure connection between Salesforce and external services. In this process, both parties present their SSL certificates, allowing them to verify each other's identity before establishing a connection. This added layer of security helps to prevent unauthorized access and ensures that sensitive data is exchanged securely during integration processes.

While other options, such as Single Sign-On (SSO) and Multi-Factor Authentication (MFA), enhance the overall security of user access and authentication in Salesforce, they do not specifically pertain to the security of outbound integrations. Data Loss Prevention (DLP) primarily focuses on protecting sensitive data from being improperly shared or leaked, rather than securing the integration channels themselves. Thus, two-way SSL stands out as the correct feature directly related to outbound integration security.