The data engineering team aims to create a multiplex bronze Delta table sourced from Kafka, featuring the schema: key BINARY, value BINARY, topic STRING, partition LONG, offset LONG, timestamp LONG. Given that the value column contains Personal Identifiable Information (PII) for certain topics, the team plans to implement Access Control Lists (ACLs) at partition boundaries to limit access to this sensitive data. Considering the schema and the requirement, which column is optimal for partitioning to enhance security?