Which sentence in the excerpt best supports the theme of harmonious living?
a spark neglected burns the house
by leo tolstoy (adapted excerpt)

there once lived in a village a peasant named iván stcherbakóf. he was comfortably off, in the prime of life, the best worker in the village, and had three sons all able to work. the eldest was married, the second about to marry, and the third was a big lad who could mind the horses and was already beginning to plough. iván's wife was an able and thrifty woman, and they were fortunate in having a quiet, hard-working daughter-in-law. there was nothing to prevent iván and his family from living happily. they had only one idle mouth to feed; that was iván's old father, who suffered from asthma and had been lying ill for seven years. iván had all he needed: three horses and a colt, a cow with a calf, and fifteen sheep. the women made all the clothing for the family, besides in the fields, and the men tilled the land. they always had grain enough of their own to last over beyond the next harvest and sold enough oats to pay the taxes and meet their other needs. so iván and his children might have lived quite comfortably had it not been for a feud between him and his next-door neighbor, limping gabriel, the son of gordéy ivánof.

as long as old gordéy was alive and iván's father was still able to manage the household, the peasants lived as neighbors should. if the women of either house happened to want a sieve or a tub, or the men required a sack, or if a cart-wheel got broken and could not be mended at once, they used to send to the other house, and each other in neighborly fashion. when a calf strayed into the neighbor's thrashing-ground, they would just drive it out, and only say, "don't let it get in again; our grain is lying there." and such things as locking up the barns and outhouses, hiding things from one another, or backbiting were never thought of in those days.

that was in the fathers' time. when the sons came to be at the head of the families, everything changed.