anot many research results can be of value to an intelligent investigator
ba research result is always valuable to an intelligent investigator
cany research result can be of value to an intelligent investigator
da research result must always be of some value to an intelligent investigator
AnswerUPSC’s answer is (c).
The author says that even plodding work can produce facts that a gifted researcher may turn to good use. So any research result can be of value to such an investigator. Options (b) and (d) turn a chance into a certainty with 'always' and 'must', which the author does not claim. Option (a) says the opposite of the author's view.
Why each option is right or wrong
(a) Wrong: the author says there is always a chance of value, not that few results are useful.
(b) Wrong: 'always valuable' turns a chance into a certainty.
(c) Correct: any result may be of value to an intelligent investigator.
(d) Wrong: 'must always' turns a chance into a certainty.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
