Correct Option: A

Forks are the drop-in replacement of MySQL. Some of the forks are MariaDB, Drizzle, Percona Server, OurDelta. MariaDB provides compatible general public license(GPL). Drizzle is better to fork than MariaDB, it is largely compatible with MySQL. OurDelta provides a combination of MySQL and MariaDB. Sphinx is a full text search engine of SQL.