Answer:
Correct answer is
2. creating a hieroglyphic writing system
3. Inventing an accurate Calendar system
Explanation:
First option is not correct as due to mostly mountainous terrain it was harder to built stronger road system.
The same goes with irrigational system, as they weren't able to develop extensive agriculture.
Also, their Empire created a first precise calendar system in the pre-Colombian America and one of the most accurate calendars based on solar year.
