How Did Observations with the Compton Gamma-Ray Observatory Show That

How did observations with the Compton Gamma-ray Observatory show that gamma-ray bursts were not coming from the Milky Way Galaxy?

A) the bursts were all so "faint" (so little energy reached us) that they must be very far away
B) the gamma-rays were all Doppler shifted, showing the sources were moving very fast
C) the gamma-rays came from all over the sky, not just the plane of the Galaxy
D) the gamma-rays were seen mostly from the direction of the planets in our solar system
E) there were so few bursts observed with the Compton Observatory that it was not possible to figure out where they were coming from