The correct option is B Lewis concept
Arrhenius concept:
According to it, an acid releases [H+] in aqueous solution while base release [OH−] ion in aqueous solution.
e.g.;
Acid:
HCl(aq)→H+(aq)+Cl−(aq)
Base:
NaOH(aq)→Na+(aq)+OH−(aq)
Bronsted Lowry concept:
An acid is a substance that donate H+ ion while a base is a substance that accepts H+ ion.
e.g.;
NH3+HCl→NH4+Cl−
Base,Accepting H+ Acid,donating H+
Lewis’s concept:
An acid is a species which accepts lone pair of e− in a reaction while a base donates that lone pair of e−
e.g.;
NH3+H+→NH4+
(Lewis's base) (Lewis acid)
Since BF3 does not have H atom, it does not fit into the definition of Arrhenius concept.
BF3 can’t be Lowry bronsted acid as it cannot donate H+ ion and not a Lowry Bronsted base because it cannot accept H+ ion since it does not have a lone pair on the central atom Boron.
BF3 is an electron deficient species as it can accept a lone pair of electrons from electron rich species.
Thus, it fits into the definition of Lewis acid. Thus, BF3 is Lewis’s acid and it can be explained on the basis of Lewis theory of acid and base.
The correct option is (C) i.e., Lewis’s concept.