The method to convert a lowercase character to uppercase is:

1. String.toUpperCase( )
2. Character.isUppercase( char )
3. Character.toUpperCase( char )
4. toUpperCase ( )

Give the output of the following code:

String P = "20", Q ="19";
int a = Integer.parseInt(P);
int b = Integer.valueOf(Q);
System.out.println(a+""+b);

Assertion (A): Integer class can be used in the program without calling a package.

Reason (R): It belongs to the default package java.lang.

1. Both Assertion (A) and Reason (R) are true and Reason (R) is a correct explanation of Assertion (A)
2. Both Assertion (A) and Reason (R) are true and Reason (R) is not a correct explanation of Assertion(A)
3. Assertion (A) is true and Reason (R) is false
4. Assertion (A) is false and Reason (R) is true

Differentiate between boxing and unboxing.