Consider the following statesments:

A horizontal pipe reduces from 10 cm to 5 cm in diameter. If the pressure head at 10 cm section is 10 metres and velocity head is 1 metre, then the

1. total head at any point is 11 metres
2. pressure head at the 5 cm section is negative
3. discharge varies proportionate to the diameter
4. datum head at all sections is constant

Of these statements