The correct answer is option 1.
Concept:
The auto storage class is the default storage class for all local variables. The variables defined using the auto storage class are called local variables. Auto stands for automatic storage class. A variable is in the auto storage class by default if it is not explicitly specified. The scope of an auto variable is limited to the particular block only.
Storage Classes:
Storage Classes are used to describe the features of a variable/function. These features basically include the scope, visibility, and lifetime which help us to trace the existence of a particular variable during the runtime of a program. C language uses 4 storage classes.
| Storage class | default value | storage area | lifetime | scope |
| auto | garbage | stack | function | function |
| static | zero | static | program | function |
| global | zero | static | program | program |
| register | garbage | stack | function | function |
Hence the correct answer is auto.


