Please submit your concern

Explanation:

This is one of those questions, you should have not attempted if you found 2-3 options close. Option 2 is correct. Although a more frequent use is ‘trees are felled or cut’, the word ‘killed’ here is not inappropriate.
In option 3, ‘paper over’ is a phrasal verb, where the meaning is different than the usual meaning of ‘paper’. One of the meanings is ‘conceal’. In option 3, it is used to mean ‘to downplay (minimize the significance of) differences (among his brothers)’ and the phrase has been used correctly.
In option 4, paper is used to mean a report or an official document.
In option 1, article ‘the’ should be removed. Suggestions look great on paper and not ‘on the paper’. ‘On paper’ is an idiom which means ‘in writing’ or ‘in theory and not in actual performance or fact’.

Hence, the correct answer is option 1.