Using a Standard List Controller, create a Visualforce page which displays a list of Accounts with links to their respective record detail pages.The page must be named 'AccountList'.
It must reference the Account standard controller.
It must have a recordSetVar equal to 'accounts'.
It must have a Visualforce apex:repeat component.
The repeater must have the var attribute set to 'a'.
The repeater must use the <li> HTML list tag
The repeater must use the apex:outputLink component to link to the respective record detail page
HINT: Record detail pages can be reached by placing a record ID at the root of the URL (e.g. '/<record id>')

I tried this code i am able to retrieve the records and clicking on each record showing  the detail page of that record.But Still Trail Head is showing error.Can someone guide me if  I am wrong


<apex:page standardController="Account" recordSetVar="accounts">
    <apex:pageBlock title="Accounts">
      <apex:repeat value="{!Accounts}" var="a">
      <li>
       <apex:outputLink value="{!URLFOR($Action.Account.view, a.id)}">{!a.Name}
       </apex:outputLink>
     </li>
   </apex:repeat>
   </apex:pageBlock> 
</apex:page>