To add web methods in VB.Net, you need to add the [WebMethod] attribute on top of the method signature. This attribute is used to indicate that the method can be invoked from a web service.
Let's go through each option to understand why it is correct or incorrect:
Option A) Add keyword to Method signature - This option is incorrect because there is no specific keyword to add to the method signature to indicate a web method in VB.Net.
Option B) Add [WebMethod] on top of the Method Signature - This option is correct because adding the [WebMethod] attribute on top of the method signature is the correct way to indicate that the method is a web method in VB.Net.
Option C) Add {WebMethod} on top of the Method Signature - This option is incorrect because the correct syntax for adding attributes in VB.Net is to use square brackets ([ ]), not curly brackets ({ }).
Option D) None of the Above - This option is incorrect because option B, which suggests adding [WebMethod] on top of the method signature, is the correct way to add web methods in VB.Net.
Therefore, the correct answer is B) Add [WebMethod] on top of the Method Signature.