The most stable carbocation from the following is :

The correct order of the following complexes in terms of their crystal field stabilization energies is :

The maximum covalency of a non-metallic group 15 element ' E ' with weakest $\mathrm{E}-\mathrm{E}$ bond is :

Identify the number of structure/s from the following which can be corelated to D-glyceraldehyde.