In an octahedral geometry,which pair of $d$-orbitals is involved in $d^2sp^3$ hybridization?

• A
  $d_{xy}, d_{yz}$
• B
  $d_{x^2-y^2}, d_{z^2}$
• C
  $d_{xz}, d_{x^2-y^2}$
• D
  $d_{z^2}, d_{xz}$