A. It is impossible to determine the deepest nesting depth because it is impossible for tag handlers that extend SimpleTagSupport to communicate with their parent and child tags
B. Create a private non-static attribute in the tag handler class called count of type int initialized to      oIncrement count in the doTag method. If the tag has a body， invoke the fragment for that body. Otherwise， output the value of count
C. Start a counter at 1. Call getChildTags（）. If it returns null， output the value of the counter.      Otherwise， increment counter and continue from where getChildTags（） is called. Skip      processing of the body.
D. If the tag has a body， invoke the fragment for that body. Otherwise， start a counter at 1. Call      getParent（）. If it returns null， output the value of the counter. Otherwise， increment the counter      and continue from where getParent（） is called.