A is incorrect: Agents generally do not automatically share memory for explicit message passing; communication often requires specific mechanisms.

B is incorrect: Using the same agent_id does not facilitate direct output-to-input passing between distinct agents; it typically identifies an agent, not its communication method.

C is correct: In typical SDK patterns, the content from one agent's execution thread is manually extracted and then injected as a user message into the subsequent agent's thread to continue the workflow.

D is incorrect: While Vector Stores are used for knowledge retrieval, they are not the primary mechanism for passing direct operational output from one agent's current processing to another as input.