To solve this question, the user needs to know what happens when a variable is declared in PL/SQL without an initial value.
The answer is:
B. NULL
If a variable is declared in PL/SQL without an initial value, its value will be NULL when it is first used in the executable section of the PL/SQL block. This means that the variable does not have a value assigned to it yet. If the variable is used in an expression or operation, it will result in a NULL value, which can cause unexpected behavior in your code.
Option A is incorrect because the variable will not have a value of 0 by default.
Option C is incorrect because declaring a variable without an initial value is legal and will not result in a compilation error.
Option D is incorrect because an exception will not be raised when a variable is declared without an initial value. It will simply have a value of NULL.