Which definition best describes Apache Spark?

Apache Spark is best described as a distributed platform for parallel data processing using multiple languages. This definition highlights the core functionality of Spark, which is designed to handle large-scale data processing tasks efficiently across clusters of machines. Furthermore, Spark supports various programming languages, including Scala, Java, Python, and R, making it versatile for different data engineering requirements.

The focus on distributed processing is crucial because Spark's architecture allows it to break down jobs into smaller tasks and execute them in parallel across a distributed computing environment. This leads to significant performance improvements, especially when dealing with large datasets, as it can leverage the resources of multiple nodes in a cluster.

While other options mention aspects of data management and processing, they don't fully encapsulate the essence of Spark. For instance, a relational database management system focuses primarily on structured data and its management, and a virtual server with a Python runtime does not address Spark’s capabilities beyond Python. Additionally, while Spark can work with streaming data, it is not limited to data streaming services but rather encompasses a broader range of data processing functionalities.