The words "carfree" and "untroubled" both have positive connotations.
- "Carfree" often suggests a lifestyle choice that emphasizes sustainability, freedom from traffic, and enjoyment of public spaces, which many people view positively.
- "Untroubled" conveys a sense of peace, calmness, or lack of stress, which is generally seen as a positive state.
Based on this analysis, the best choice is:
D) They each have a positive connotation.