Option B: 'Befogged' means 'incapable of clear thought, confused'.
'Puzzled' means 'unable to understand, perplexed'.
This word means the same as 'befogged'.
Hence this word replaces the italicized word and option B is correct.
Option A: 'Panicky' means 'feeling or characterized by uncontrollable fear or anxiety'.
Option C: 'Surprised' means 'feeling or showing surprise'.
Option D: 'Happy' means 'feeling or showing pleasure or contentment'.
These words do not mean the same as the given word. So, they cannot replace it.
Hence options A, C and D are incorrect.