Default value is "JSP" in the spec, but this value is invalid for Simple Tag => mandatory <body-content> makes sense to me.
j2eecertiface might be outdated (before the Simple Tag days)
I think this explains it; basically it doesn't make sense to have a default value for <body-content> anymore, so it is a mandatory tag without a default value. Instead you would have to specify "JSP" explicitly as the value, making (a) the correct answer to your question as of Servlet 2.4. Of course, if you don't know what else to put there, sensible defaults are "JSP" for classic tags and "scriptless" for simple tags, but these aren't enforced.
Charles Lyons (SCJP 1.4, April 2003; SCJP 5, Dec 2006; SCWCD 1.4b, April 2004)
Author of OCEJWCD Study Companion for Oracle Exam 1Z0-899 (ISBN 0955160340 / AmazonAmazon UK )
Specifies the format for the body of this tag. The default in JSP 1.2 was "JSP" but because this is an invalid setting for simple tag handlers, there is no longer a default in JSP 2.0. A reasonable default for simple tag handlers is "scriptless" if the tag can have a body.