The correct answer is 1. Monochromatic
Explanation:
The word "monochromatic" means one tone or color. This word derives from the prefix "Monos", which means one, and the word "chromatic" that refers to color or tones. In this context, if an object contains only one color or tone, the object is considered monochromatic. In this context, the most appropriate word to describe an automobile that is all blue is the word monochromatic. Also, other words are not related to tones or colors, for example, a monolith is a type of geographical structure and lithograph is an artistic method.