Which group remains when blue is removed from the primary-colour group?

Correct answer: Red and Yellow

The traditional primary-colour set is red, yellow, and blue. The question asks us to remove blue from that exact list. The two colours left are therefore red and yellow, making option B correct. Green is a secondary colour produced by mixing yellow and blue, orange is produced by mixing red and yellow, and violet is not part of the original primary set in this exercise.