Answer:
d. [Ar] 4s²
Explanation:
The ground state electron configuration is the electron configuration of an atom with lower energy levels. The electron configuration for Titanium (Ti) is:
Ti = [Ar] 4s²3d² -By Aufbau principle-
For Ti²⁺, the ground state electron configuration is removing the 3d² electrons.
That means that ground state electron configuration for Ti²⁺ is:
d. [Ar] 4s²
I hope it helps!