Question

she get up dawn (in/at/by)

Answer 1

she get up by Dawn..

Answer 2

While the formation of this sentence does not allow for any of these prepositions to be used, if it is corrected to something like 'She gets up ___ dawn', then the right answer will be 'by'.

This sentence without the preposition by itself is not very grammatically accurate and hence it needed some amount of correction.