Answer: Python and R, SQL and Python

High Concurrency clusters are designed for **multi-user environments** where many users run queries at the same time. According to the Databricks community reference, these clusters support **SQL, Python, and R**, but **do not support Scala**. This limitation exists because High Concurrency clusters run each user’s code in **separate, isolated processes** to ensure better security and stable performance. **Scala runs on the JVM and cannot be isolated this way**, so it is not supported. Therefore, **any language combination that includes Scala is not supported** on High Concurrency clusters. This is why options containing Scala (such as SQL and Scala, Python and Scala, or Scala and R) are invalid. Reference: https://community.databricks.com/t5/data-engineering/when-to-use-high-concurrency-clusters-what-are-the-benefits/m-p/26520#M18553

Author: LeetQuiz Editorial Team