If a student accidentally mixes red and blue which colour will be formed?

Correct answer: Violet

The governing concept is the traditional RYB colour-mixing model used in elementary art education. Red and blue are primary colours, and mixing them produces violet, a secondary colour. Green requires yellow plus blue, while orange requires red plus yellow; yellow alone is not the product of mixing red and blue. Actual pigments can produce slightly different violet or muted results depending on their composition, but the expected school-level answer is unambiguous. Therefore, option B is correct.