I agree with the person above - I'd say the correct answer is B. The greenhouse effect is changing Earth's atmosphere.
A is incorrect because the excerpt says that the atmosphere keeps the Sun's heat from leaking away into space. C is incorrect because it is the greenhouse effect that keeps the planet warm. D is not even mentioned in the text, which means that only B is correct.
The tied one is the opinion for me
Hopes it helped
I believe the answer is 14. you multiply 4*3 then add 2. hope this helps, have an amazing day :)