Final answer:
Apache Cassandra is an open source NoSQL database known for its scalability and performance in handling large volumes of data.
Step-by-step explanation:
Apache Cassandra™ is a massively scalable open source NoSQL database. The correct answer to this question is option b) NoSQL.
As a NoSQL database, Apache Cassandra offers a high level of scalability and performance, particularly in environments with large amounts of data and high write and read throughput. Unlike traditional SQL databases which use a relational model, NoSQL databases like Cassandra use a non-relational, distributed data store that can handle large volumes of unstructured, semi-structured, and structured data.