The given sentence needs to be filled with an adverb of place. An adverb of place will tell you where the action happens or where someone is going. Thus ‘at home’ is the apt answer. Hence option B is correct. Whereas ‘at morning’ is an adverb of time, which tells us when the action happened, i.e. the time. So option A is incorrect. Similarly ‘thrice’ cannot be used, because it is an adverb of frequency. It indicates how often the action takes place, i.e. the rate of occurrence. Hence option C is incorrect. ‘Carefully’ is an adverb of manner. It explains the way people do things and is not used to indicate a place. Therefore option D is incorrect.