If a star does not emit a significant amount of visible radiation, what could you conclude? a)it will not be able to be seen b)it is a black hole c)it is a very intense star d)it is not a very intense star

The answer is a) it will not be seen, or to expound it will be very difficult to be seen. Stars does not give off one type of radiation, light radiation emitted from the stars is just one, however the other types of radiations emitted by the stars are of different wavelength, most of the ranges of these wavelengths does not fall under the visible wavelength as such we cannot see them.