The correct option is B. The rule is when one of the nouns connected by 'or' or 'nor' is plural then the verb must be plural and the plural subject should be placed next to the verb. Here, 'Surendra' is singular subject and 'his friends' is plural subject thus 'have been' is used which is plural verb. Hence, 'Have been' is the best fit according to the rule
I believe the answer is Monochromatic
A color scheme could be categorized as monochromatic if it's derives only from single based hue using additional tints, tones, and shades.
The usage of these will alter the brightness and the saturation of the color just like what we see in the painting.