Which of the following features allows you to constrain user's ability to modify query restrictions?

The feature that allows you to constrain a user's ability to modify query restrictions is the "sql_always_where" parameter. This parameter is utilized in LookML to ensure that specific conditions are always applied to the SQL query generated behind the scenes, regardless of any filters or dimensions a user might choose to add or change in their query.

By implementing "sql_always_where," developers can enforce necessary restrictions on the dataset, improving both data security and integrity. This is especially useful in scenarios where certain data should not be accessible or where context-sensitive filtering is required to maintain the accuracy of metrics.

In contrast, while "sql_always_having" also applies conditions to queries, it is specifically related to HAVING clauses in SQL, which typically filter aggregate results rather than filtering at the row level like the WHERE clause. "View_label" is more focused on the naming and display aspects within the Looker interface rather than query constraints, and "always_join" is used to enforce that a join must always be included in a query, rather than constraining users' ability to change query restrictions.