Looking at the answer options:

1. 'Is a regulatory limitation' --> CORRECT. The MZFM is a manufacturer's limit and will be in the AFM, as approved by the authority / regulator.

2. 'Is calculated for a maximum load factor of +3.5 g' --> INCORRECT. The MZFM is calculated for a max load factor of +2.5 g

3. 'Is based on the maximum permissible bending moment at the wing root' --> CORRECT. The MZFM is a structural limitation designed to protect the wing root. During flight the lift acting on the wings picks up the fuselage where most of the weight is concentrated. This causes structural stress at the wing root as the wings bend upwards.

4. 'Is defined on the assumption that fuel is consumed from the outer wings tank first' --> INCORRECT. The optimum method of using fuel, to protect the wing bending, is to use any central tank first and then wing tanks last. Fuel in the wing tanks lowers the bending of the wings.

5. 'Is defined on the assumption that fuel is consumed from the centre wing tank first' --> CORRECT. As described in the answer above.