In the model User you have the code shown below. When saving the model and model.is_admin is set to true, which callback will be called?
before_save :encrypt_data, unless: ->(model) { model.is_admin }
after_save :clear_cache, if: ->(model) { model.is_admin }
before_destroy :notify_admin_users, if: ->(model) { model.is_admin }
a. encrypt_data
b. clear_cache
c. notify_admin_users
d. None of these callbacks will be called when is_admin is true.