Which Liquid statement checks if a user is logged in before displaying a specific section?

The statement that correctly checks if a user is logged in before displaying a specific section is {% if customer %}. In Shopify's Liquid templating language, the 'customer' object becomes available when a user is authenticated and logged into their account. In this context, if 'customer' exists and contains data, it implies that the user is indeed logged in.

This construct allows developers to conditionally render content based on the user's authentication status. When the condition is met, any code inside the block after the {% if customer %} statement will be executed, allowing for a tailored experience or functionality designed for logged-in customers.

Other options do not fulfill the requirement as they either check for the absence of a customer or do not specifically address customer login status in the correct manner. For instance, checking with {% unless customer %} would execute the code block if the customer is not logged in, while the loop statement {% for customer in customers %} iterates over an array of customers, neither of which serves the purpose of a direct logged-in check. The statement {% if logged_in %} is also not valid in Shopify's Liquid since it does not use 'logged_in' as an official attribute within the framework.