Read the passage from Animal Farm.

Boxer was the admiration of everybody. He had been a hard worker even in Jones's time, but now he seemed more like three horses than one; there were days when the entire work of the farm seemed to rest on his mighty shoulders. From morning to night he was pushing and pulling, always at the spot where the work was hardest. He had made an arrangement with one of the cockerels to call him in the mornings half an hour earlier than anyone else, and would put in some volunteer labour at whatever seemed to be most needed, before the regular day's work began. His answer to every problem, every setback, was "I will work harder!"—which he had adopted as his personal motto.

Which statement best explains how details in the passage develop the central idea that Boxer is dedicated to the farm?

A) The details show that everybody likes Boxer.
B) The details show that Boxer is inventive.
C) The details show that Boxer misses Jones.
D) The details show that Boxer is tireless.