VXML: Regarding <prompt> in <object> and <subdialog>

Hi,
 
I have a doubt regarding the processing of <prompt> during the collect phase
for <object> and <subdialog>.
 
Section 2.1.6.2.2 of VXML specfication says that:
"If a <subdialog> or <object> is visited, the prompts are queued based on
the item's prompt counter and the prompt conditions. Grammars are not
activated. Instead, the input collection behavior is specified by the
executing context for the subdialog or object. The queue is not played
before the subdialog or object is executed, but instead should be played
during the subsequent input collection."
 
Consider the object example..
<form id="gather_pager_message">
  <object name="message"
      classid="builtin://keypad-text-input">
   <prompt>
     Enter your message by pressing your keypad once
     per letter.  For a space, enter star.  To end the
     message, press the pound sign.
   </prompt>
  </object>
  <block>
    <assign name="document.pager_message" expr="message.text"/>
    <goto next="#confirm_pager_message"/>
  </block>
</form>

The explanation says that the user is first prompted for the pager message,
then keys it in...
 
Here, how is the <prompt> within the <object> processed?
 
a) The interpreter selects and queues the prompt, and plays it (flushes)
before issuing the request to the platform to execute the object... (or)
b) The interpreter just selects the prompt and pass it as a parameter, in
the request to the platform to execute the object. The object implementation
only decides when and how to play the prompt.
 
Which of the above mentioned options is correct?
 
The playing of <prompt> written within a <subdialog> is also a bit
ambiguous. Could someone explain with an example.
 
Thanks
Rajesh