Black holes in orbit around a normal star are detected from the earth due to the frictional heating of infalling gas into the black hole, which can reach temperatures greater than 106 K. Assuming that the infalling gas can be modelled as a black body radiator, then the wavelength of maximum power lies
(a) in the visible region
(b) in the X-ray region
(c) in the the microwave region
(d) in the gamma-ray region of electromagnetic spectrum.
