黃金閱讀 RUNNING WATER ON MARS - 英檢

Paragraph 3 Some scientists speculate that Mars may have enjoyed an extended
early Period during which rivers, lakes, and perhaps even oceans adorned its
surface. A 2003 Mars Global Surveyor image shows what mission specialists
think may be a delta─a fan-shaped network of channels and sediments where a
river once flowed into a larger body of water, in this case a lake filling a
crater in the southern highlands. Other researchers go even further,
suggesting that the data provide evidence for large open expenses of water on
the early Martian surface. A computer-generated view of the Martian north
polar region shows the extent of what may have been an ancient ocean covering
much of the northern lowlands. The Hellas Basin, which measures some 3,000
kilometers across and has a floor that lies nearly 9 kilometers below the
basin’s rim, is another candidate for an ancient Martian sea.

8. According to paragraph 3, images of Mars’ surface have been interpreted
as support for the idea that
A) the polar regions of Mars were once more extensive than they are now
B) a large part of the northern lowlands may once have been under water
C) deltas were once a common feature of the Martian landscape
D) the shape of the Hellas Basin has changed considerably over time

想請問這題答案B為什麼對呢?
我是從這句找答案的
A 2003 Mars Global Surveyor image shows what mission specialists
think may be a delta─a fan-shaped network of channels and sediments where a
river once flowed into a larger body of water, in this case a lake filling a
crater in the southern highlands.
^^^^^^^^^^^^^^^^^^看到這裡講southern highland
就不覺得northern lowlands不能選....
我答案是選C 因為有deltas
還是說我找錯句子了?
謝謝大家!

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