Refer to the exhibit. CUBE_1 and CUBE_2 must use the G.729r8 codec when communicating. Which action completes the configuration?

Setting dtmf-relay sip-notify is for DTMF signaling, not for enforcing a specific voice codec like G.729r8.

While a voice class can contain codec lists, deploying it to CUBE_2 alone doesn't guarantee CUBE_1 will use G.729r8, and it's not the final step to activate existing changes on CUBE_1.

After modifying codec preferences or other significant parameters on a Cisco Unified Border Element (CUBE) dial peer, a 'clear call active voice compact' or 'clear dial-peer voice <tag>' command is often required to ensure that existing calls or future calls initiated through that dial peer pick up the new configuration, such as a specific codec like G.729r8. This action ensures the updated codec settings become active without requiring a full CUBE reload.

A transcoder is used to convert between different codecs when direct negotiation fails or is not desired; it doesn't enforce G.729r8 directly between two CUBEs that should be able to negotiate it.