The correct option is A electron deficient.
According to Lewis concept BF3 is act as Lewis acid, which are electron deficient.
$BF_3$ is a trigonal-planar molecule because electrons can be found in only three places in the valence shell of the boron atom. As a result, the boron atom is sp2 hybridized, which leaves an empty 2pz orbital on the boron atom. BF3 can therefore act as an electron-pair acceptor, or Lewis acid.