In the following sentence, a part of the sentence is underlined. Below are given alternatives to the underlined part, which may improve the sentence. Choose the correct alternative. In case no improvement is needed, choose the option ‘No improvement’. A section of farmers also called upon Collector S.Sivarasu to ensure that all eligible farmers were included in the list of beneficiaries under the income support scheme announced by Prime Minister Narendra Modi recently. ?

Option 4 : No improvement

Explanation: Call upon somebody- to ask formally for someone to do something. Since, the sentence is given in the past tense, called upon is apt to use.
Examples: They called on the company to reverse its decision.
                    If you're ever called upon at work to give a talk, the very prospect of 'getting up there in front of all those people' can be intimidating.
                    I should now like to call upon the finance director to take you through the results.

Therefore, the correct answer is option 4.