To answer this question, you need to understand the concept of XPath axes. XPath axes are used to navigate through the elements and nodes in an XML document.
Let's go through each option to understand why it is correct or incorrect:
Option A) following - This option is a valid XPath axis. The "following" axis selects all the nodes that come after the current node in the document order.
Option B) followed - This option is not a valid XPath axis. There is no "followed" axis in XPath, so this option is incorrect.
Option C) ancestor - This option is a valid XPath axis. The "ancestor" axis selects all the ancestors of the current node.
Option D) attribute - This option is a valid XPath axis. The "attribute" axis selects all the attributes of the current node.
The correct answer is B) followed. This option is not a valid XPath axis because there is no "followed" axis in XPath.