This question is missing the excerpt. I will not add it here because it is quite long, but the complete question can be easily found online. The excerpt belong to "The Travels of Marco Polo".
Answer:
The option that indicates that the author's purpose is to inform readers about travel south of Madagascar and Zanzibar is:
A. The author shares facts and specific details about the difficulty of sailing in the region.
Step-by-step explanation:
Marco Polo was a Venetian adventurer who lived from 1254 to 1324. "The Travels of Marco Polo" is a book based on his trips and discoveries and written by Rusticiano de Pisa, who met Polo and had the chance to hear the adventurer himself tell the stories.
In the excerpt that can be found online, the author is informing readers about travel south of Madagascar and Zanzibar. The passage is written as it it were Polo himself describing the difficult travel conditions in the region. He provides readers with facts about the currents that prevent ships from going a certain direction. According to him, the currents are always southward. A ship may take 20 days to go a certain way, but three months to return precisely because of the currents.