Correct Answer:
C. MongoDB
The correct answer is MongoDB. MongoDB is a popular example of a NoSQL database, specifically a document-oriented database. NoSQL databases, which stands for "Not only SQL," are a class of non-relational database management systems that provide a mechanism for storage and retrieval of data other than the tabular relations used in relational databases.
Key characteristics of NoSQL databases like MongoDB include:
- Flexible Schema: They often allow for dynamic schemas, meaning the structure of data can vary from document to document.
- High Scalability: Designed for horizontal scaling, making them suitable for handling large volumes of data and high traffic.
- Variety of Data Models: They can store data in various formats such as key-value, document, column-family, or graph.
In contrast, MySQL, Oracle, and PostgreSQL are all examples of traditional Relational Database Management Systems (RDBMS) that use SQL (Structured Query Language) for defining and manipulating data, adhering to a rigid, predefined schema.