PLS HELP ASAP...A triangle has side lengths of (10m-5) centimeters, (6m-2) centimeters, and (8n+4) centimeters. Which expression represents the perimeter, in centimeters, of the triangle?
1. 12n+16m−7
2. 16m+8n−3
3. 12n+5m+4
4. 12n+9m