Explanation
A. The passage does not present the greenhouse theory as questionable but rather reinforces it with recent scientific data and acknowledges earlier oversights regarding sulfates and solar cycles.
B. While the passage does mention that models now incorporate the effects of sulfates, the main point is not solely about the importance of the modified models but the overall support for the greenhouse effect as a cause of warming.
C. The passage does not compare the current rate of temperature increase to what was originally estimated by the greenhouse theory, nor does it discuss the equilibrium temperature.
D. (Correct Response) The passage supports this option by discussing how recent studies and data have strengthened the link between the increase in atmospheric temperatures and greenhouse gases, despite the complicating factors of airborne sulfates and solar energy variations.
E. The passage does not condition the reasonableness of the greenhouse theory on its combination with the solar-fluctuation theory. It merely acknowledges additional factors without suggesting that they are required for the greenhouse theory to be considered valid.
The passage outlines how recent scientific findings support the warming trend and the significant role of greenhouse gases, in line with the assertion in option D.