听力原文：Governments from Singapore to South Korea are increasingly lifting restrictions o

n gambling. But gamblers do not have to wait for new casinos to open to place their bets: They can just use their mobile phones. Telecommunications analysts predict that Asia will catch up soon. British Informa, a telecom and media consulting company, forecasts that close to 100 million people in the Asia-Pacific region will use mobile phones to place bets in 2010, half of the users globally. The mobile gambling market in Asia is still limited by the lack of suitable phones. Another obstacle for gaming operators is the unclear legal situation in many places.

What is one of the main reasons that restrict the mobile gambling market in Asia？

A．Restrictions from the governments.

B．The technological restrictions.

C．The unclear situation of mobile gambling.

D．The insufficient number of gaming operators.