A molecule of NH3BF3has a dative bond. The donor atom in the bond is and acceptor atom is .
The correct options are
N in NH3 has a lone pair of electron. Boron (B) is electron deficient in BF3 as it has only six electrons in its valence shell. A dative bond is formed between these molecules, where N donates its lone pair to Boron (B). Thus, nitrogen acts as donor and boron acts as acceptor.