Which of the following is not a standard for cordless telephony?

The correct answer is C. UMTS.

CT-2 is a digital cordless telephone system developed in the United Kingdom in the early 1980s. It was the first digital cordless telephone system to be widely deployed, and it remains in use in some countries today.

DECT is a digital cordless telephone system developed in Europe in the late 1980s. It is the most widely used digital cordless telephone system in the world.

PHS is a digital cordless telephone system developed in Japan in the early 1990s. It is a very popular system in Japan, and it is also used in some other countries.

UMTS is a third-generation mobile phone technology. It is not a cordless telephone system.