43 CFR 3100.3-1 - Enforceability.
(a) No option to acquire any interest in a lease shall be enforceable if entered into for a period of more than 3 years (including any renewal period that may be provided for in the option) without the approval of the Secretary.
(b) No option or renewal thereof shall be enforceable until a signed copy or notice of option has been filed in the proper BLM office. Each such signed copy or notice shall include:
(1) The names and addresses of the parties thereto;
(2) The serial number of the lease to which the option is applicable;
(3) A statement of the number of acres covered by the option and of the interests and obligations of the parties to the option, including the date and expiration date of the option; and
(4) The interest to be conveyed and retained in exercise of the option. Such notice shall be signed by all parties to the option or their duly authorized agents. The signed copy or notice of option required by this paragraph shall contain or be accompanied by a signed statement by the holder of the option that he/she is the sole party in interest in the option; if not, he/she shall set forth the names and provide a description of the interest therein of the other interested parties, and provide a description of the agreement between them, if oral, and a copy of such agreement, if written.