Read the text and answer the multiple-choice question by selecting the correct response. Only one response is correct.

Analysis of prehistoric air cornered in small bubbles below the polar ice sheets and of the composition of ice close those bubbles suggests a correlation between carbonic acid gas levels within the Earth’s atmosphere and world temperature over the last a 160,000 years. Estimates of worldwide temperature at the time air within the bubbles were cornered believe activity the relative abundances of atomic number 1 and its heavier atom, deuterium, within the ice close the bubbles. once world temperatures are comparatively low, water containing hydrogen atom tends to condense and precipitate before reaching the poles; so, ice deposited at the poles once the world temperature was cooler contained comparatively less hydrogen atom than ice deposited at hotter global temperatures. Estimates of worldwide temperature supported this data, combined with analysis of the carbonic acid gas content of air cornered in ice deep below the polar surface, recommend that in periods of postglacial warming carbonic acid gas within the Earth’s atmosphere inflated by more or less 40%.

Q. In the passage, the author is primarily concerned with doing which of the following?

(A) Describing a new method of estimating decreases in global temperature that have occurred over the last 160,000 years
(B) Describing a method of analysis that provides information regarding the relation between the carbon dioxide content of the Earth’s atmosphere and global temperature
(C) Presenting information that suggests that global temperature has increased over the last 160,000 years
(D) Describing the kinds of information that can be gleaned from a careful analysis of the contents of sheets