The correct answer is - A. city officials chose to fill in nearby bodies of water to create more land.
The surrounding area of Boston has been occupied by shallow bodies of water, mainly swampy waters. The local authorities saw the potential of these parts, and decided to fill them up with soil, and so they did. As the swamps were getting filled and were gradually destroyed, much more land was available for the people to start building and settle in. As that process was going on, the city of Boston was becoming larger and larger, and in only 260 years it doubled its initial population.