Which scenario is the requirement level enforced?

You create a custom field and set the requirement level to Business Required.
For which scenario is the requirement level enforced?
A. A user creates a record through the web interface but the required field is not on the current form.
B. A user creates a record by using one of the mobile clients.
C. A developer creates a record by using custom code.
D. A user creates a record by using the data import functionality.