When to Zero Rate VAT and when to Standard Rate

When making a supply of a vatable product, what rate of VAT (standard or zero) is applied in each of the following examples:

A UK VAT registered business supplying goods to a customer with a billing & delivery address outside the UK.

A UK VAT registered business supplying goods to a customer with a billing address in the UK, but delivery is outside the UK.

A UK VAT registered business supplying goods to a customer with a billing address outside the UK, but delivery address in the UK.

Rate Supply of goods