To answer this question, the user needs to know about Javadoc tags and their purpose in documenting Java code.

Now, let's go through each option and explain why it is right or wrong:

A. @author: This is a valid Javadoc tag that is used to indicate the author of the code or the documentation.

B. {@link}: This is a valid Javadoc tag that is used to create a hyperlink to another class, method, or field in the code documentation.

C. @serialField: This is a valid Javadoc tag that is used to document the fields of a serializable class.

D. @arg: This is not a valid Javadoc tag. The correct Javadoc tag for documenting method arguments is @param.

Therefore, the answer is:

The Answer is: D. @arg