The correct option is : (b) SF4
Explanation:
For neutral molecules,
No. of electron pairs = No. of atoms bonded to it + 1/2[Gp. no. of central atom-Valency of central atom]
For ions,
No. of electron pairs = No. of atoms bonded to it + 1/2[Gp. no. of central atom - Valency of central atom ± No. of electrons]