All these islands are very beautiful, and of quite different shapes, easy to be traversed, and full of the greatest variety of trees reaching to the stars. I think these never lose their leaves, as I saw them looking as green and lovely as they are wont to be in the month of May in Spain. –Letter to Gabriel Sanchez, Christopher Columbus Which explanation tells why this source is either biased or unbiased? A. It is biased because it contains the author’s opinions. B. It is biased because the author did not witness the event firsthand. C. It is unbiased because the author tells the events from different perspectives. D. It is unbiased because the author provides details that can be proven.