WhichXSLifstatementchecksfortheexistenceofahomepageattributewithinanSTSUniversalUserXMLstructure?()A.<xsl:iftest="//stsuuser:AttributeList/stsuuser:Attribute[attr=‘homepage‘]">B.<xsl:iftest="//stsuuser:AttributeList/stsuuser:Attribute[@name=‘homepage‘]">C

A.<xsl:iftest="//stsuuser:AttributeList/stsuuser:Attribute[attr=‘homepage‘]">

B.<xsl:iftest="//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‘])>