听力原文： I'd like to talk to you about a television program that's going to be shown tonight, and that I want you all to watch. It will present work that's currently being done by geologists off the coast of Hawaii. The only active underwater volcano in the U. S. is located there.It's growing and may reach the surface of the ocean in about 50, 000 years—not very long from now in geological time. Anyway, geologists are setting up an unmanned observatory at the top of this volcano, which is located about 70 miles southeast of Hawaii and about 3, 000 feet below the surface of the ocean. They plan to install seismometers, thermal sensors, chemical detectors, video cameras, and other equipment to monitor the volcano's activities. Then they'll hook up an electric cable between the observatory and the mainland so they can receive information electronically from these instruments. Geologists are pretty excited about this project, and I hope you are too. It ties in very nicely with the work we've been doing in class on volcanoes. Watch the program about it tonight, and be prepared to discuss it tomorrow.
Who is the speaker?
A．A television announcer.
B．A member of a research team.
C．A teacher.
D．A network executive.