What is common way of saving, retriving simple data between program clossing and starting - C application

There's a simple C application made using GTK+2 Also it has simple data on the interface and the application needs to load the last used values before closing, when the application starts again.

I found few methods to save load data.

1. saving a txt file and loads it.
2. using a DB.

Since I'm a beginner with C, either way I need to do a RnD and start implementing. I need to know the best/standard/effective method which use by C programming professionals for this kind of scenario.