Which colour combines with the primary colour blue to make violet?

Correct answer: Red

Red combines with blue to produce violet in the traditional paint colour model, so red is correct. The three key relationships are yellow plus blue equals green, red plus yellow equals orange, and red plus blue equals violet. Yellow with blue would make green, not violet. Green and orange are secondary colours, so they are not the primary-colour partner requested. Actual pigment shades may differ slightly, but the school-level rule remains clear.