Four 2-centre 3-electron bonds and two 3-centre 2 -electron bonds
Four 2-centre 2-electron bonds and two 3-centre 2 -electron bonds
Two 2-centre 2-electron bonds and four 3-centre 2 -electron bonds
Four 2-centre 2-electron bonds - 4 B-H
Two 3-centre 2 -electron bonds - 2 B-H-B (one Electron of B and on electron H)
Option (3) is correct
Diborane structure involves Four 2-centre 2-electron bonds and two 3-centre 2 -electron bonds