Your form submission rate tracks:

The total number of views for all the pages your form appears on that also have your HubSpot tracking code on them
The total number of submissions divided by the total number of views for the form
The total number of times the form has been submitted across all your pages
The total number of times your form appears across all your pages

The correct answer is:

The total number of submissions divided by the total number of views for the form.