The correct answer to which lines from "In Flanders Fields" supports the theme "the living carry on what the dead cannot" is the third option "Take up our quarrel with the foe; / To you from failing hands we throw The torch;".
When the author says that others should "take up our quarrel" he means that the ones who stayed should take responsibility for the fights the ones who died can't anymore. By saying "To you from failing hands we throw the torch" the author conveys that those who can't deal anymore with the quarrels, who have now "failing hands" are handing in these same quarrels to "you", to the living ones, "the torch", the mission of taking these quarrels ahead. So, the correct answer to which lines from "In Flanders" supports the theme "the living carry on what the dead cannot" is the third option "Take up our quarrel with the foe; / To you from failing hands we throw The torch".
The correct answer couldn't be "In Flanders fields the poppies blow /Between the crosses, row on row" because those lines don't support the idea that "the living carry on what the dead cannot", it only expresses how to "poppies", here a symbol for life, "blow", or still goes on. Thus, the correct answer couldn't be the first option.
The correct answer couldn't be "The larks, still bravely singing, fly / Scarce heard amid the guns below" because these lines are telling about people's resistance, and life's resistence. How "the larks", small birds that represent people, are still bravely singing despite the guns below. So, the correct answer couldn't be the second option.
The correct answer couldn't be "We shall not sleep, though poppies grow In Flanders fields" because, through these lines, the author is affirming that the quarrel is not dead, as "we shall not sleep" due to the fact that poppies still grow, there is still life to be defended and preserved. These lines are encouraging those who stayed alive, but not necessarily supporting the theme that they should carry what those who died cannot. Hence, the correct answer couldn't be the fourth one.
