Which of the following actions would be most likely to resolve this error ?

Errors caused by "duplicate keys" typically arise when an operation, such as a join, an upsert, or an attempt to enforce uniqueness, encounters multiple identical keys where only one is expected. Identifying and removing these duplicate keys from the problematic dataset directly resolves the root cause of such errors, ensuring data integrity for subsequent operations.

While changing a join type might alter the outcome in the presence of duplicates, it often masks the underlying data quality issue rather than resolving the core problem of having duplicate keys.

Increasing partitions primarily addresses performance and data skew issues, not logical errors caused by duplicate keys in the data itself.

Restarting a cluster is a general troubleshooting step for transient issues or environment refreshes, and it does not resolve data-specific errors like duplicate keys.