You should use the C page's path. First you should convert the C page's path to a resource then adapt it to Page or Node to get the jcr:title property. You can use Sightly's JavaScript Use API by passing page C's path and the required property (jcr:title).
or try below
${resolver.getResource('/path/to/page/C/jcr:content')['jcr:title']}
if the above one doesn't work,try 1st step.