A variable is a name given to a memory location to store some value. Since the memory location can store different values during execution of a program, the name used to refer to it, is called a variable.Since variables are a part of identifiers, they follow the same naming conventions. Like identifiers, a valid variable name can start with an alphabet or an underscore ( _ ) and later have a combination of one or more letters, digits and underscores.A few examples of valid variable names are : sum,total,average_marks, etc.When creating a variable, we should mention the type of data (for example, integer or character) that it would store. This is called the data type of that variable.In a C program, variables should be declared before their usage.The format for declaring a variable is data_type variable_name;.For example:int count; // int is the data type and count is the variable nameThe above declaration can also be combined with initialisation. In such a case, the format for declaring a variable is data_type variable_name = constant_value;.We shall learn more about data types and constants in the later sections.Given below is an example of declaring and initialising a variable in the same line:int count = 9; // Here the variable count is being initialised to a constant value 9 Invalid#include <stdio.h>void main() { printf("age : %d", age); int age = 34; // this is the declaration statement} Valid#include <stdio.h>void main() { int age = 34; printf("age : %d", age);}Select the correct statements from the given statements.Variable is an identifier which is used to store data.The value stored in a variable is fixed. It cannot be changed once it is initialised to a value.Variable is the name given to a memory location.The type of data stored in a variable is specified by its data types.