If a Company Uses the Allowance Method to Account for Doubtful

If a company uses the allowance method to account for doubtful accounts, when will the company's Stockholders' equity decrease?

A) At the date a customer's account is written off
B) At the end of the accounting period when an adjusting entry for bad debts is recorded
C) At the date a customer's account is determined to be uncollected
D) When the accounts receivable amount becomes past due