Which phrase best conveys the sentiment of jealousy toward a brother's new car?

The phrase that best conveys sentiment of jealousy toward a brother's new car is the one that uses "envious" in relation to seeing the brother's new car. This expression captures a feeling of wanting something that someone else possesses, in this case, the new car belonging to the brother. It directly reflects an emotional response of envy, which is the sentiment the question is asking about.

The other options do not effectively communicate jealousy. One option suggests jealousy about an old car rather than a new one, which does not align with the original sentiment. Another option expresses happiness, which is contrary to the feeling of jealousy, indicating a positive reaction instead. The last option shows indifference, indicating a lack of emotional response altogether, which is not consistent with the feeling of jealousy either.