The geometry of a complex species can be understood from the knowledge of type of hybridisation of orbitals of central atom. The hybridisation of orbitals of central atom in and the geometry of the complex are respectively
(i) , tetrahedral
(ii), square planar
(iii) , octahedral
(iv) , square planar
The answer is the option (i) , tetrahedral
Boron in the excited state has 2s orbitals which are not paired and one electron which is in the p-orbital. In hybridization, the hybridization is formed, and tetrahedral geometry is observed.
Electronic configuration of boron;