Our project…finished by the end of the week ,so there is no reason why you shouldn’t plan a weeked getaway.
a. must have b.could have c.will have d.have
Is it an obligation and requires the modal:must have… or is it an future foreseen and we should use the future perfect?
It should be future perfect (“will have finished”).
By the way, I notice that your use of spaces is often haphazard. Learning how to use spaces correctly makes a big difference to the quality of your writing for relatively little effort.