The correct answer is D. Unusual.
Exotic means strange or unusual, especially in a way that is attractive or exciting. It can also refer to something that comes from a foreign country or region.
Beautiful means having a pleasing appearance or aspect. It can also refer to something that is morally good or admirable.
Colourful means having a lot of different colours. It can also refer to something that is lively or exciting.
Excellent means very good or of high quality. It can also refer to something that is successful or accomplished.
In this case, the correct answer is D. Unusual. This is because the word “exotic” is used to describe something that is strange or unusual, especially in a way that is attractive or exciting. The other options are not as accurate descriptions of the word “exotic.”