When adjusting a manual slack adjuster, how much free play should there be on the pushrod with the brakes released?

1. About 1.3 to 1.9 centimetres (1/2 to 3/4 inch) of push-rod travel when pulled by hand
2. At least 5.0 centimetres (2 inches) when pulled by hand
3. Between 7.5 and 10.0 centimetres
4. Zero, there should be no movement at all