Read the excerpt from into the unknown by stewart ross.

the mové steamed south along the coast, crossed the equator in the afternoon, and reached the broad mouth of the ogooué by evening. chugging steadily upriver, over the next two days the steamer carried kingsley between banks of overhanging forest to the small settlement of lambaréné, 130 miles from the sea. from here, she waited to catch a small stern-wheel steamer, the éclaireur, bound for ndjolé, ninety miles upstream, which she reached on june 23.

which text feature would best support the details in the excerpt?

a map of the ogooué river
a photograph of mary kingsley
a diagram of the mové steamer
a chart of mary kingsley’s travel dates