Europeans carried a hidden enemy to the Indians: new diseases. Native peoples of America had no immunity to the diseases that European explorers and colonists brought with them. Diseases such as smallpox, influenza, measles, and even chicken pox proved deadly to American Indians.
I would say B. Eustress because this stress is a "good" type of stress that aided you in performing well. Eustress is stress that is "good," and helps you.
