Which of the following 3G standard is used in Japan?

Cdma2000
TD-SCDMA
UMTS
UTRA

The correct answer is B. TD-SCDMA.

TD-SCDMA (Time Division-Synchronous Code Division Multiple Access) is a 3G mobile telecommunications standard developed by China Mobile. It is the only 3G standard that is not based on the GSM family of standards. TD-SCDMA was first deployed in China in 2009 and has since been adopted by several other countries, including Japan.

CDMA2000 is a 3G mobile telecommunications standard that is based on the CDMA family of standards. It was developed by the CDMA Development Group (CDG) and is used in many countries around the world, including the United States, Canada, and South Korea.

UMTS (Universal Mobile Telecommunications System) is a 3G mobile telecommunications standard that is based on the GSM family of standards. It was developed by the Third Generation Partnership Project (3GPP) and is used in many countries around the world, including Europe, Asia, and Africa.

UTRA (UMTS Terrestrial Radio Access) is the radio access technology used by UMTS. It is based on the Wideband Code Division Multiple Access (WCDMA) technology.