What is the entitlement of a party who was prevented by the other party from fully performing his obligations?

1)

Entitled to claim payment of the agreed sum less costs of rectifications or omissions.

2)

Entitled to claim payment of the agreed sum without deduction because innocent party was not at fault.

3)

Entitled to claim payment on a quantum meruit basis for work which has already been done.

4)

Entitled to claim payment on a quantum meruit basis for all the work contracted to be done.