[xsl] XPath for selecting element without an attribute

["Perrin, Aaron" <perrina@xxxxxxx>]

Hello,

I'm curious of whether it's possible to build an XPath able to select an
element without an attribute.

For example, consider the following:

<A>
  <B> One </B>
  <B C="true"> Two </B>
  <B C="false"> Three </B>
</A>

I'm hoping to find the B element without the attribute, but not any others.

I have been trying things like the following //A/B[@C=''], attempting to key
off an empty string, but haven't had any luck.  Also, I'm going against a
schema which I can't change.  I'm assuming that this is possible, right?

Thanks for any help,

Aaron