Question

Zn, Cd, and Hg are not regarded as transition elements on the basis of electronic configuration because
1 they do not have electrons in d-subshell
2 their d and s-subshell remain fully filled in ground and higher oxidation states
3 their s-subshell remain incomplete in ground and ionic state 
4 their penultimate shell remains completely filled in ground and in higher oxidation state 

Answer 1

the answer is the option 4.

Answer 2

transition metals properties comes from their chemistry involves electron from d-orbitals. 
Zn,Cd,Hg chemistry involves only the electron in their s-orbitals hence (4) option is correct