Multiple Choice
Cygnus A, a strong radio source, is also designated 3C 405. What does the "3C" stand for?
A) "3C" stands for the Third Cambridge Catalog, an important list of radio sources.
B) This radio source is a Type 3C radio source as opposed to a Type 1A or a Type 2B.
C) Cygnus A was discovered through a joint program run by Cambridge, Connecticut, and Calgary universities.
D) A chopper is a device needed to cut off and delineate a signal from a source, and three such choppers are required to isolate an intelligible signal from Cygnus A.
Correct Answer:

Verified
Correct Answer:
Verified
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