Final answer:
The argument is valid as the conclusion can be logically inferred from the premises.
Step-by-step explanation:
The argument is valid. To determine validity, we need to examine if the conclusion follows logically from the premises. In this case, the conclusion, 'Some people who are making life a little worse are people who live in a city,' can be inferred from the premises. From premise A, we know that all people who drive contribute to air pollution. From premise B, we know that all people who contribute to air pollution are making life a little worse. Since people who live in a city can be included in the group of people who contribute to air pollution, the conclusion is valid.