Correct option is A
Option
(a) 2, 1, 3, 4 is the correct order of the given sentences.
Explanation (why this order is correct):
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2 is the best opening because it introduces the main topic and importance of research.
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1 logically follows by defining what research is (“It is a process…”). The pronoun “It” clearly refers to “Research” in sentence 2.
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3 comes next because “This” refers to the research process and classifies it into two types: theoretical and applied.
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4 is the best conclusion because it explains the final step—results are documented and peer-reviewed to ensure credibility, completing the research cycle.