The correct option is A H2O
Bronsted acid is a species that is capable of accepting a proton and bronsted base is a species that donates a proton.
Here H2O will act as both bronsted acid and base.
H2O+NH3⇌OH−+NH+4
Here, water donates its H+ to NH3 and act as a bronsted acid
H2O+H2S⇌H3O++HS−
Here , water accept the H+ ions by its lone pair and act as bronsted base.
Hence it amphoteric in nature.
NaOH will act only as bronsted base since the OH− ion abstract H+ ion
BF3 does not act as bronsted acid or base since it electron deficient to abstract H+ and it does not have hydrogen to donate.
CH4 does not donate its hydrogen because their bonds are covalent in nature and they form precise stable octet structure.