Explanation:

To create a public-facing form that can directly create records in Salesforce without requiring login, the most common declarative solution is to use an app from the Salesforce AppExchange.

Apps like FormAssembly, Formstack, or Conga Grid allow organizations to build web forms that submit data straight into Salesforce objects, all configured declaratively with clicks rather than code.

These apps handle public accessibility, validation, and secure data submission efficiently.

Why not the others?
B. Process Builder automates processes based on Salesforce data changes but does not create public-facing forms.
C. Email-to-case creates cases from emails sent to a specific address, which is not a form solution and doesn’t meet the requirement for a declarative, public web form.