Final answer:
Water transport is the most cost-effective mode of transportation, with lower environmental impact and cheaper public bus services as viable alternatives.
Explanation:
Water transport is the cheapest mode of transportation due to lower associated costs compared to land or air transport. Shipping by water has been noted to have a lower impact on the environment than road or air transport. Additionally, public bus services are usually cheaper than railways for long-distance travel.
Learn more about Modes of transportation here:
https://brainly.com/question/43170754
