What is achebe’s purpose for writing this passage?

to explain that people with closed minds may not notice wonderful things around them, and their description of a situation may not include everything
to explain the significance of marco polo’s journeys in our culture’s growth and to highlight the most important lessons he taught about the places and customs he saw
to explain that people who read a text with a closed mind will likely miss important details and come away with an incomplete perspective
to explain the significance of the great wall of china and the damage caused by ignoring it when describing a culture’s growth and development over time