What does the thermography depend on
A) Television cameras C) Photograph negatives
B) Infrared energy D) Given temperatures

A．expensive because of the high voltage the machine requires
B．a time-consuming process
C．inexpensive after the machine is purchased
D．an unsafe procedure

A．consumers with international business opportunities
B．subscribers with a cheap and efficient link
C．formal roles to oversee its users
D．telecommunications services to users