Choose the option which is opposite of the given word:
 Dull
A. Wise
B. Shining
C. Colourful
D. Foolish

Hint: Dull means something not bright, vivid or lustrous. It is an adjective.

Complete answer:
From the hint given to us, we know that dull means something not bright, vivid or lustrous. We also know that it is an adjective. Hence we can infer that the opposite of must means bright and lustrous.
Wise means having a good sense of judgement or knowledge based on experience. It is an adjective. We observe that it does not match the meaning of the opposite word, which we had inferred. Hence option A is not the correct answer.
Shining means being bright or lustrous. It is an adjective. We observe that it matches the meaning of the opposite word, which we had inferred. Hence option B is possibly the correct answer.
Colourful means very vibrant. It is an adjective. We observe that it does not match the meaning of the opposite word, which we had inferred. Hence option C is not the correct answer.
Foolish means very unwise and dumb. It is an adjective. We observe that it does not match the meaning of the opposite word, which we had inferred. Hence option D is not the correct answer.
Hence, we can conclude that option B is the correct answer.
Note: Semantically, colourful can also be the opposite of dull. However, we have taken the literal meaning of the words into consideration in the solution. According to which, shining is the correct opposite.