In National Carriers Ltd V Panalpina (Northern) Ltd Why

In National Carriers Ltd v Panalpina (Northern) Ltd why was a contract for the ten year lease of a warehouse found to be frustrated?

A) Because the warehouse had been built without the correct planning permission
B) Because the warehouse no longer complied with regulations for the storage of flammable goods - the purpose for which it had been rented.
C) Because the warehouse was subject to an arson attack and repairs would take 18 months to complete
D) Because road works undertaken by the local council made access and so use of it impossible for a period of 18 months