Which colour tendency is created by adding a little yellow to red?

Correct answer: Reddish orange

The governing concept is hue bias caused by unequal proportions. Red and yellow combine in the orange range; because only a little yellow is added, red remains the dominant visual influence. The mixture therefore has a reddish-orange tendency, so option D is correct. Bluish violet requires blue and red, yellowish green requires yellow and blue, and grey blue is not the expected result of this two-colour warm mixture.