Review the description below of a database named DB$100,$ then select the database type that most closely fits DB$100\text{'}$s description.

DB$100$ contains a billing schema that is hosted by three database instances. The organization has three campuses, and each campus hosts one database instance. The New York database instance contains mostly New York billing data, the Singapore database instance contains mostly Singapore billing data, and the London database instance contains mostly London billing data. To retrieve billing information, a database client connects to the database instance on the same campus and performs a query; that database instance communicates with the other instances, if needed, to obtain all of the needed data.

a$.$

DB$100$ is a distributed database.

b$.$

DB$100$ is an online$-$transaction processing $($OLTP$)$ database.

c$.$

DB$100$ is an online$-$analytical processing $($OLAP$)$ database.

d$.$

DB$100$ is a parallel database.