Which of the Following Circumstances Result in a Defective Formation

Which of the following circumstances result in a defective formation?

A) when a certificate of limited partnership is not properly filed
B) when a certificate of amendment is not executed or signed
C) when the liability of partners extends to debts that cannot be satisfied with the existing capital of the limited partnership
D) when a creditor fails to enforce the personal guarantee and recover payment from the limited partner who personally guaranteed the repayment of the loan