A shop owner offers the following discount options on an article to a customer :

Successive discounts of 10% and 20%, and then pay a service tax of 10%

Successive discounts of 20% and 10%, and then pay a service tax of 10%

Pay a service tax of 10% first, then successive discounts of 20% and 10%

Which one of the following is correct?

1 only is the best option for the customer.

2 only is the best option for the customer.

3 only is the best option for the customer.

All the options are equally good for the customer.