Which of the following is a best practice to measure time

Which of the following is a best practice to measure time taken by a process for execution?

1. System.getProcessingTime()
2. System.getCurrentTime()
3. System.nanoTime()
4. System.currentTimeMillis()
5. None of these

System.nanoTime takes around 1/100000 th of a second whereas System.currentTimeMillis takes around 1/1000th of a second.