(a) If the borrower fails to make any payments due under or provided to be paid by the terms of the note or security instrument, the note shall be considered in default for the purposes of this subpart.

(b) The failure to perform any other covenant under the note or security instrument shall be considered a default: Provided, The lender, because of such default, has exercised its rights under the note or security instrument and accelerated the debt.

(c) The failure to make any payment or to perform any covenant under the first conventional note and mortgage by reason of which the holder thereof declares a default as evidenced by formal written declaration of said default to the Commissioner and the lender by the holder of the first note and mortgage, shall be considered a default under the insured loan.

(d) If such defaults as defined in paragraphs (a), (b), and (c) of this section continue for a period of 30 days, the lender shall be entitled to receive the benefits of insurance hereinafter provided.