Questions: What crop's discovery by John Rolfe saved Jamestown from ruin?

The answer is A. Tobacco

John Rolfe is credited with the successful cultivation of tobacco in the Jamestown colony, which became a highly profitable cash crop. His introduction of a sweeter strain of tobacco in 1612, which was more palatable to European tastes, significantly boosted the colony's economy and ensured its survival.

Indigo was not a major crop in Jamestown during its early years. It became more prominent in the southern colonies, particularly in South Carolina, much later in the 18th century.

While corn was an important staple crop for the survival of the Jamestown settlers, it was not the crop that saved the colony economically. The indigenous peoples taught the settlers how to grow corn, which helped them survive, but it was not a cash crop like tobacco.

Hemp was grown in the colonies for its fibers, which were used for making ropes and sails, but it did not have the same economic impact as tobacco in Jamestown.