>>211637115
>Should it be
>>昼に何時から何時までやすみますか
>Or
>>昼何時から何時まで休みますか
Honestly speaking, they sound almost identical to me from any point of view, like in politeness or other nuances.
Likewise, the supposed answers must be >1)nothing 2)に 3)に 4)nothing
in the question you attached, but it's far from uncommon or unnatural to say 2) without に or 3) without に depending on the situation. So I think it wouldn't be much worth meticulously memorizing their "proper usages" as textbooks say for time-related-expressions unless you have to pass some exams.