An automated email that you send has a high click-through rate, but the landing page that it promotes has a low conversion rate. Which element would benefit most from contextual marketing?

A personalized subject line in the email.
A smart CTA in the email to show different wording to visitors.
A smart form on the landing page to ask different questions of visitors who come from the email.
A personalization token on the landing page that displays the first name of visitors who come from the email.