The colourless species is: VCl3, VOSO4, Na3VO4, [V(H2O)6]SO4.H2O

In Na3VO4, the oxidation state of vanadium is:
3 + x - 8 = 0
x = 5
Vanadium is in +5 oxidation state.
Electronic configuration of V = [Ar]3d³ 4s²
Electronic configuration of V⁵⁺ = [Ar]3d⁰ 4s⁰
It does not have unpaired electrons. Hence, Na3VO4 is a colourless species.