Assertion (A): In Python, the strings are mutable.

Reasoning (R): In strings, the values are enclosed inside double or single quotes.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Assertion (A): Slicing a string involves extracting substring(s) from a given string.

Reasoning (R): Slicing does not require start and end index value of the string.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Assertion (A): Indexing in a string is defined as positive and negative indexing.

Reasoning (R): In forward and backward indexing, the indices start with 1^st index.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Assertion (A): The following code snippet on execution shall return the output as: False True

str1 "Mission 999"  
str2 = "999"  
print(str1.isdigit(), str2.isdigit())

Reasoning (R): isdigit() function checks for the presence of all the digits in an inputted string.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.