Why `Ti^(4)` complex are diamagnetic?

Why Ti^(+4) complexes are diamagnetic?

Which complex is diamagnetic:

Which of the following coordination complex is/are diamagnetic?

True or False : All inner orbital complexes are diamagnetic.

Using valence bond theory, show that [Ni(CN)_4]^(2-) complex is diamagnetic in nature. [Atomic number of Ni is 28].

Which of the following complexes diamagnetic: