In Azure Databricks notebooks, the %<language> command (also known as magic commands) is used to switch between different programming languages within individual cells. This allows a single notebook to support multiple languages while maintaining the primary language specified when the notebook was created.

Why Option A is correct:

• The % prefix followed by the language name (e.g., %scala, %sql, %r, %python) is the standard syntax for language-specific magic commands in Databricks
• This command tells the notebook interpreter to execute the current cell using the specified language, regardless of the notebook's default language
• For example, in an R notebook, you can use %scala to run Scala code in a specific cell, or %sql to run SQL queries

Why other options are incorrect:

• Option B (@<Language >): The @ symbol is not used for language switching in Databricks; it's sometimes used for annotations in specific languages but not for cell language specification
• Option C (\$$<language >]): This syntax is not valid for language switching in Databricks notebooks
• Option D (\$<language >)): This syntax is not recognized by Databricks for changing cell languages

This approach enables data engineers to leverage the strengths of different languages within a single notebook workflow, such as using R for statistical analysis, Scala for distributed data processing, and SQL for data querying, all while maintaining clean, organized code.