If orange must be lightened and slightly muted which sequence is more controlled?

Correct answer: First a little blue then white as needed

The relevant concept is stepwise control of saturation and value. Blue is near the complement of orange, so a very small amount can reduce its brightness or saturation. White should then be added gradually to raise the value and make the mixture lighter. Option B is therefore the most controlled sequence. Much black risks an overly dark, dull result, while adding unrelated colours together makes the final change difficult to judge.