A force \(F\) acting on an object varies with distance \(x\) as shown below:

The force is in Newton and \(x\) is in meters. The work done by the force in moving the object from \(x = 0\) to \(x = 6\) m is:
1. \(18.0\) J
2. \(13.5\) J
3. \(4.5\) J
4. \(9.0\) J