What are the options for open source NoSQL database in a Cloud environment?

Most ofthecloud-computing providers support Open Source NoSQL databases. Some ofthese databasesare:
I. Apache CouchDB :It isa document based NoSQL databasefromApache Open Source. It iscompatible withCouch
Replication Protocol. Itcan communicatein nativeJSON and can store binary data verywell.
II. HBase :It isa NoSQL databasefor use withHadoop based software. It isalso availableas Open SourcefromApache. It isa
scalableand distributed BigData database.
III. MongoDB :It isan open source databasesystemthat offersaflexible data modelthatcan be used to store various kinds of data.
It provides high performanceand always-on userexperience.