What made me initially skip past answer A was that it stated once the rain cloud "formed" over the atlantic. The passage specifically said that the rain cloud "passes" from above the atlantic.... doesn't this imply that it exists prior to reaching the atlantic....as in already "formed"? Is interpreting "formed" the way I did a mistake in determining that "formed"/created does not equal "passed"/traveled over?

I learned a valuable lesson to not make such a quick determination based on definition alone.

Congrats!

from what I've experienced and have been taught in another course - Necessary assumptions have softer language like sometimes, may, etc. Strong language for sufficient assumptions.