Should Checkboxes be Checked or Unchecked by default in forms

I have a quiz creation form, in which an admin is required to fill the quiz name, details, number of maximum attempts and similar admin level configuration items.
The admin should configure if the quiz can be reattempted even if the a candidate had passed in the previous attempt. So I used a checkbox here. The confusion is; is there any standard rule for default state of checkboxes in forms?

The image shows the 2 possible options that I could have in the form.
Please advice which is the correct representation, with respect to any documented standards.