Which syntax is used in Liquid to comment out lines?

The correct syntax for commenting out lines in Liquid is {% comment %} ... {% endcomment %}. This method allows developers to include comments within their Liquid templates without them being rendered in the final output. It is particularly useful for adding notes, explanations, or temporarily disabling code during development without affecting the functionality of the template.

The use of the {% comment %} tag alongside {% endcomment %} clearly delineates the start and end of the comment block, ensuring that any content enclosed within these tags will be ignored during execution. This syntax contributes to better code organization and documentation, making it easier for developers to collaborate or revisit their code later.

Other potential comment syntaxes listed do not align with Liquid's requirements, reflecting different contexts in other programming languages or templating systems. Thus, the correct option accurately represents the best practice for commenting in Liquid.