Answer: the answer is b: sp3d
Explanation: BrF3 has a Bent T shaped structure with Br as a central atom bonded with three F atoms (three bond pairs) and two lone pairs. Hence , the hybridization would be sp3d. Br atom has 7 electron in its outer most shell. After the bond formation of BrF3 molecule we have 3 bond pairs+ 2 lone pairs