. . . . . . . . prevents you from using undeclared variable in your code.

The correct answer is: Option Explicit On

Option Explicit is a statement in Visual Basic that forces you to declare all variables before you use them. This helps to prevent errors and makes your code more readable.

Option Implicit is a statement in Visual Basic that allows you to use variables without declaring them. This can be useful for simple code, but it can also lead to errors.

Explicit Off and Implicit Off are not valid statements in Visual Basic.

Here is an example of how Option Explicit can help to prevent errors:

“`
Option Explicit

Dim x
x = 10

MsgBox x
“`

This code will generate an error because the variable x has not been declared.

Here is an example of how Option Implicit can lead to errors:

“`
Option Implicit

x = 10

MsgBox x
“`

This code will not generate an error, but it will also not work as expected. The variable x will be assigned the value of 10, but it will not be declared as a numeric variable. This means that you cannot use it in any arithmetic operations.

In general, it is best to use Option Explicit in your code. This will help to prevent errors and make your code more readable.