Answer
Infrared.
Work Step by Step
We know that the shorter the wavelength, the greater the scattering.
So the best way to take a picture of the center of our galaxy that is filled with dust, (the dust as low-density hydrogen increases the scattering and absorbs a lot of light coming to us), is to use the longest wavelength available.
And since the infrared is the longest among these 3 types, the astronomer needs to use it.
