Final answer:
The text illustrates that the Jamestown settlement was surrounded by marshes that were a breeding ground for disease-carrying mosquitoes, contributing to the high mortality rate among the colonists. The correct option is A.
Step-by-step explanation:
The quote from the text explains that James Town was surrounded by marshes full of disease-carrying mosquitoes. When the Virginia Company settlers chose the marshy peninsula up the James River for their colony, they did not foresee the troubles that this environment would pose.
The brackish water was unfit to drink, and the marsh served as an ideal breeding ground for mosquitoes, which facilitated the spread of diseases and contributed to the high mortality rate among the colonists. This is consistent with other historical records which detail the harsh realities faced by the settlers, including food spoilage, attacks from local Indians, and overall poor health leading to the death of many colonists during the early years of the Jamestown settlement.
Hence, Option A is correct.