Refer to the exhibit. An engineer is securing a customer's network. Which command completes this configuration and the engineer must use to prevent a DoS attack?

`neighbor ebgp-multihop` allows establishing eBGP sessions between non-directly connected peers but does not, by itself, provide security against DoS attacks by validating TTL values.

`ebgp'multihop` appears to be a syntactical error or typo; the correct command is `ebgp-multihop`.

The `ttl-security` command is a BGP feature used to protect eBGP sessions by verifying the Time-to-Live (TTL) value of incoming BGP packets. It ensures that packets originate from expected distances (e.g., direct neighbor with TTL 255) and drops those with unexpected TTLs, mitigating certain DoS attacks.

`neighbor ttl-security` is part of the command structure, but 'ttl-security' is the core keyword representing the feature being enabled to complete the security configuration, typically followed by `hops <value>`.