Waiver Agreement to Third Amended and Restated Credit Agreement among Centennial Energy Holdings, Inc. and Lender Banks

Please refer to the Third Amended and Restated Credit Agreement dated as of May 8, 2014 (the “Credit Agreement”) among Centennial Energy Holdings, Inc. (the “Company”), various financial institutions and U.S. Bank National Association, as administrative agent (in such capacity, the “Agent”). Capitalized terms used but not defined herein shall have the respective meanings set forth in the Credit Agreement.

The Company has advised the Banks that Fidelity Exploration & Production Company (“Fidelity”), a direct wholly owned subsidiary of WBI Holdings, Inc. (“WBI”) and indirect wholly owned subsidiary of the Company, has sold or intends to sell all or substantially all of its assets in a series of transactions and that WBI may sell its interest in Fidelity, as more fully described in certain filings made by MDU Resources Group, Inc. with the SEC prior to the date hereof (the “Fidelity Disposition”). The Company has requested a waiver of certain provisions of the Credit Agreement to permit such disposition.

Accordingly, the Majority Banks hereby waive the following provisions of the Credit Agreement, in each case solely with respect to (and to the extent required to permit) the Fidelity Disposition: (a) clause (y) of the first proviso to Section 7.02 of the Credit Agreement (it being understood that the Fidelity Disposition shall not count against the limitation of 20% of total consolidated assets that may be sold by the Company and its Subsidiaries in any fiscal year); (b) the final proviso to Section 7.02 of the Credit Agreement (which begins “provided, further,”); and (c) to the extent applicable, the provisions of Section 7.03 of the Credit Agreement limiting consolidations and mergers.

The provisions of Sections 10.15 (GOVERNING LAW AND JURISDICTION) and 10.16 (WAIVER OF JURY TRIAL) of the Credit Agreement shall apply to this waiver letter as if set forth herein in full, mutatis mutandis.

This waiver letter may be executed in counterparts and by the parties hereto on separate counterparts. A signature page hereto delivered by facsimile or in a .pdf or similar file shall be effective as delivery of an original counterpart. This waiver letter shall become effective when the Agent has received signature pages hereto signed by the Majority Banks.