Which of the following methods is suitable for preventing an iron frying pan from rusting?

The most suitable method for preventing an iron frying pan from rusting is applying a coat of zinc. This is called galvanization. Grease and paint are also used for prevent rusting from iron. However, in case of iron frying pan, grease and paint cannot be applied because when fan will be heated and washed again and again, the coating of grease and paint would get destroyed.