Which of these events most confirms Margaret Frink's bias about American Indians?

A.
When the Indians offered the Frinks horses for trade

B.
Rumors of Indian attacks

C.
When the Frinks were followed by Indians

D.
When the Indians visited the Frinks' camp

Without more context or information, it is difficult to determine which event would most confirm Margaret Frink's bias about American Indians. However, based on the limited information provided, option B - rumors of Indian attacks - may align more closely with potential biases or preconceived notions Margaret Frink might hold about American Indians.