The Most Likely Low Interference Region of the Radio Spectrum

The most likely low interference region of the radio spectrum for communication with other civilizations is the water hole,the part of the spectrum

A) at the radio emission of hdrogen in our Galaxy.
B) at the radio emission of OH.
C) at the radio emission of noise from Earth's atmosphere.
D) between the radio emissions of hydrogen and OH.
E) near the radio band where water in the Earth's atmosphere strongly absorbs energy.