Pick up the correct statement from the following?

The length of the lap in a compression member is kept greater than bar diameter x (Permissible stress in bar / Five times the bond stress) or________?

Economical depth of a plate girder corresponds to________?

The significant wave height is defined is the average height of the________?

If the average bending stress is 6 kg/cm2 for M 150 grade concrete, the length of embedment of a bar of diameter d according to I.S. 456 specifications, is________?

Sapwood consists of________?