The correct answer is: C) I worked for dawn until dusk.
From dawn until dusk means from early morning to early evening, meaning that the author of the diary wants to tell that he/she has worked a lot. It makes a change in the tone because it implies a period of time in which efford has been put an as result the writer must be tired.
The other answers tell us at what time an event took place, this usage of a time reference only gives us that information, it locates us in time.