In the following question, an incomplete statement followed by fillers is given. Pick out the best filler to complete the incomplete statement, correctly and meaningfully. Although the initial reports suggested a minor issue, __________.

Explanation: The phrase "Although the initial reports suggested a minor issue" creates an expectation that the reality was different or more serious. The best option is (A), as it logically follows by indicating that further investigations exposed a major problem. Option (2) contradicts the structure, as ignoring the problem does not logically follow the contrast set by "although." Option (3) does not indicate any significant development. Option (4) fails to show a contrast between initial reports and later findings. Thus, (1) is the best choice as it maintains coherence and contrast in the sentence.