Which XSL if statement checks for the existence of a homepage attribute within an STS Universal User XML structure?（）

A、<xsl:if test="//stsuuser:AttributeList/stsuuser:Attribute[attr='homepage']">

B、<xsl:if test="//stsuuser:AttributeList/stsuuser:Attribute[@name='homepage']">

C、<xsl:if-exists="//stsuuser:AttributeList/stsuuser:Attribute/custom:Homepage">

D、<xsl:if-exists="//stsuuser:AttributeList/stsuuser:Attribute[@name='homepage'])>