Which of the following pairs of d-orbitals will have electron density along the axes?

1. d_z²,d_xz

2. d_xz,d_yz

3. d_z²,d_x²-y²

4. d_xy,d_x²-y²

A pair of d-orbitals having electron density along the axes is: 

1. $d_{z^2},$ $d_{xz}$

2. $d_{xz},$ $d_{zy}$

3. $d_{z^2},$ $d_{x^2-y^2}$

4. $d_{xy},$ $d_{x^2-y^2}$