The lanthanide contraction is responsible for the fact that:

1. Zr and Y have about the same radius .

2. Zr and Zn have the same oxidation state.  

3. Zr and Hf have about the same atomic radius .

4. Zr and Nb have a similar oxidation state.

The incorrect statement among the following is:  

The reason for lanthanoid contraction is:

1. Negligible screening effect of 'f' orbitals

2. Increasing nuclear charge

3. Decreasing nuclear charge

4. Decreasing screening effect

Actinide contraction is mainly related to:
1. Poor shielding by 5f subshell
2. Extraordinary decrement in Z_eff
3. Both (1) and (2)
4. Strong shielding by 5f subshel