The correct option is B (i) is correct (ii) is incorrect
As BF3 is a Lewis acid and NH3 is a Lewis base,so, NH3 donates its lone pair to BF3 and forms a dative bond.
In (i) NH3 donates its lone pair to BF3, whereas in (ii) BF3 donates its electron to NH3.
So, (i) is correct.