The statements regarding ‘B’ and Al areI) Boron is a bad conductor of heat and electricityII) Aluminium hydrides are stableIII) Maximum covalency of Boron is 4The correct statements are

Maximum covalency of B is 4,due to presence of only three valency orbitals ,those are one ns orbital and three np orbitals.Boron is bad conductor of electricity and heat,because boron is non metal.