[amp_mcq option1=”in” option2=”by” option3=”at” option4=”No improvement” correct=”option4″]
The correct answer is D. No improvement.
The sentence “Putting in hard work to help others is what he likes from his heart” is grammatically correct and conveys the intended meaning clearly. The preposition “in” is not necessary in this sentence, as it does not add any meaning. The preposition “by” is also not necessary, as it does not indicate the means by which he likes to help others. The preposition “at” is also not necessary, as it does not indicate the location of his hard work.
Therefore, the sentence “Putting in hard work to help others is what he likes from his heart” is correct and does not need to be improved.