Im not 100% but i think the answer is d. :}
Dill is a huge liar. He lies to make others like him.
"Among other things, he had been up in a mail plane seventeen times, he had been to Nova Scotia, he had seen an elephant, and his granddaddy was Brigadier General Joe Wheeler and left him his sword."
This passage allows us to see into the inner struggle and loneliness of the character. This is revealed in the phrase "interior gloom" while he faces the "open lattice" but he was not looking at anything at all. He was engrossed in his own thoughts and feelings of a closure or an ending of life implied in the phrase "the fire had smouldered to ashes." The surroundings was so silent and cold as revealed in the words "damp, mild air," "cloudy evening" and "so still."