Iprofess, in the sincerity of my heart, that i have not the least personal interest in endeavouring to promote this necessary work, having no other motive than the publick good of my country, by advancing our trade, providing for infants, relieving the poor, and giving some pleasure to the rich. i have no children, by which i can propose to get a single penny; the youngest being nine years old, and my wife past child-bearing. which statement effectively uses a quotation to relate swift’s claim that he has no personal motive for making this proposal?

I believe the correct answer is - According to Swift, he has “not the least personal interest in endeavouring to promote this necessary work.” 
This sentence shows that he has no personal motive for making this proposal, especially given that his wife cannot have any more children, so the proposal doesn't affect him in the slightest. This means that he made the proposal for the sole purpose of helping others, not himself. The first and the last option are incorrect as they don't even use the quotations, and the third option doesn't show that he has no personal gain out of this.