Question

I ___ probably spend the holidays with my family.(shall, should, could,may)​

Answer 1

I shall probably spend the holidays with my family

Answer 2

I __shall_ probably spend the holidays with my family

The correct option among all the options given in the question, for this particular blank is shall.

This is because here the speaker is somewhat confused in his/ her statement which can be understood by the use of term probably.

So, shall is the most appropriate and significant option among the given options for this answer.