Answer:
b. An ultraviolet telescope in orbit around the Earth
Step-by-step explanation:
Ultraviolet telescope is a type of telescope which is used to determine a ultraviolet portion present in electromagnetic spectrum, that is between the portion seen as visible light portion and X-rays portion.
An ultraviolet telescope should be placed at the earth's orbit because earth have a ozone layer of its own. The ozone layer helps to filter most of the ultraviolet rays coming towards it.
Thus the correct option is (b).