Here's why:

* Titanium oxide (TiO2) is extremely stable and has a very high melting point.

* Carbon (C) is a powerful reducing agent at high temperatures and can effectively reduce TiO2.

* Other reducing agents, such as hydrogen (H2) or aluminum (Al), are not strong enough to reduce TiO2 effectively due to its high stability.

The reaction:

TiO2 + 2C → Ti + 2CO

This reaction occurs at very high temperatures in a process called the Kroll process, which is the primary method for producing titanium.