Why does Quito, Equator has very little changes to the daylight hours
throughout the year?

Because of the position on the equator, the change in rotation of the Earth on its axis throughout the year doesn't affect it much. Unlike the poles, Quito is almost constantly in direct view of the sun. So, because of lack of change in rotation, the daylight hours are hardly varied as Quito is almost constantly in more or less the same spot in relation to the sun.

the area between the graph and the t axis

i think its c if i'm wrong