a) Hive is not a relational database, but a query engine that supports the parts of SQL specific to querying data
b) Hive is a relational database with SQL support
c) Pig is a relational database with SQL support
d) All of the mentioned

Answer: a
Explanation: Hive is a SQL-based data warehouse system for Hadoop that facilitates data summarization, ad hoc queries, and the analysis of large datasets stored in Hadoop-compatible file systems.