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This Reading Comprehension question is from the June 2004 LSAT.
As usual, let's jot down some quick paragraph summaries as we read this. They'll be helpful later, especially with "main point" questions like this one, which come up a lot on the LSAT.
Paragraph 1: Knowledge/regulation lags in oil industry
Paragraph 2: Regulation lagged in mid-19th century
Paragraph 3: Groundwater contamination a problem
Paragraph 4: Knowledge to protect groundwater is lacking
This gives us a very basic view of the structure and argument in the passage, which will be helpful for this and other questions. Now, let's pre-phrase a main point for this passage. Given the summaries, it should be something like "The scientific knowledge and regulation of the oil industry has often addressed safety issues too slowly." We see right away that choice D fits well, mentioning how science/regulation don't move quickly enough to address safety problems. Let's look at the other choices quickly:
A) Too narrow in scope. This passage really focuses on how science and law move too slowly to protect the public from oil-related contamination. The passage is about a lot more than just a technical analysis of contamination, as this answer choice suggests. Something this narrow in scope can't be the whole passage's main point.
B) Too narrow in scope, once again. This choice talks only about the facts of one incident. This passage is about the broad trend of science/regulation not keeping pace with oil's dangers.
C) The opposite of what we want. This choice says that hindsight is the only option, and the passage's criticism is that hindsight is inappropriately relied on instead of being proactive to prevent disasters. If hindsight were the only option, this criticism, which is the heart of the passage's argument, would be contradicted. The main point surely doesn't contradict the passage's main argument.
D) Correct.
E) Again, too narrow in scope to be the main point. This passage talks about scientific knowledge and regulation, but this choice talks only about regulation. That's too narrow.
Remember:
1) Use summaries of each paragraph, which can be just a few words written alongside each paragraph in your text booklet, to help answer questions. It won't take long and should help a lot. Pre-phrase an answer to save time and work more accurately when there's a definite answer, as there was here (there's just one main point).
2) Avoid answers that are too broad or narrow in scope (the "main point" must address the whole passage, not just one little detail) and answer choices that say the opposite of the answer we're looking for (in this case, "main points" that contradict the passage's argument). These two simple categories, as we've seen time and time again, can eliminate virtually all wrong answer choices on the RC (and Arguments).
