Which scenario could be described as garish?

The word "garish" is often used to describe something that is excessively bright, flashy, or showy, particularly in a way that is considered to be unpleasant or tasteless. In the context of the choices provided, a loud and colorful carnival parade involves vibrant colors, loud sounds, and an overall spectacle that can be overwhelming to the senses. This scenario fits well with the definition of "garish," as the extravagant use of bright colors and noise can create a sense of visual and auditory excess.

In contrast, the other scenarios reflect a sense of calmness, subtlety, or simplicity. A quiet evening by the fireplace evokes warmth and tranquility, while a monochromatic art exhibit emphasizes a limited color palette that is usually more subdued. Lastly, a nature hike through serene landscapes promotes harmony and natural beauty, which are at odds with the concept of something being garish. Thus, the carnival parade stands out as the most fitting example of a scenario described as garish.