Answer:
An illustration of Ma Robert
Explanation:
Ma Robert (meaning: <em>Robert's mom</em>) was the steamboat used by David Livingstone, a Scottish physician and missionary. It was named in honor of his wife Mary and son Robert.
The given excerpt tells us about the steamboat and its numerous flaws. The text feature that would best support these details is an illustration of Ma Robert.
The man mentioned in this passage is named David Livingstone, not Charles. The fact that a wrong name is mentioned doesn't matter, because a photo of Livingstone wouldn't be fitting either way. This passage is not about him. The same goes for the map of the African continent. The steamboat was used for expeditions on its territory, but that is not the main point. A chart of many uses of steam is also not right, because it can be applied to many things, not just this boat.
This is why an illustration of Ma Robert, like the one pictured below, would be the best feature.
