Here's how to figure that out:

* Electron Configuration: The electron configuration of titanium is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d².

* Shell Numbers: Each number in the configuration represents an electron shell (1st, 2nd, 3rd, and so on).

* Counting Shells: Notice the highest shell number is 4. However, since the 3d subshell is also occupied, we count it as a separate shell. Therefore, titanium has 3 electron shells (K, L, and M).