Exhibit C

JOINT FILING AGREEMENT

PURSUANT TO RULE 13d-1(k)(1)

The undersigned acknowledge and agree that the Schedule 13D to which this agreement relates is filed on behalf of each of the undersigned and that all subsequent amendments to the Schedule 13D to which this agreement relates shall be filed on behalf of each of the undersigned without the necessity of filing additional joint filing agreements. The undersigned acknowledge that each shall be responsible for the timely filing of such amendments, and for the completeness and accuracy of the information concerning it contained therein, but shall not be responsible for the completeness and accuracy of the information concerning the others, except to the extent that it knows or has reason to believe that such information is inaccurate. This agreement may be executed in any number of counterparts and all of such counterparts taken together shall constitute one and the same instrument.

Dated: December 8, 2016

[Signatures on following page]

FR Bison Merger Sub, Inc.
By:	/s/ Matthew S. Raben
	Name: Matthew S. Raben
	Title: Vice President and Secretary
FR Bison Holdings, Inc.
By:	/s/ Matthew S. Raben
	Name: Matthew S. Raben
	Title: Vice President and Secretary
First Reserve Energy Infrastructure Fund II, L.P.
By: First Reserve Energy Infrastructure GP II, L.P., its general partner
By: First Reserve Energy Infrastructure GP II Limited, its general partner
By:	/s/ Matthew S. Raben
	Name: Matthew S. Raben
	Title: Director, Legal
First Reserve Energy Infrastructure GP II, L.P.
By: First Reserve Energy Infrastructure GP II Limited, its general partner
By:	/s/ Matthew S. Raben
	Name: Matthew S. Raben
	Title: Director, Legal
First Reserve Energy Infrastructure GP II Limited
By:	/s/ Matthew S. Raben
	Name: Matthew S. Raben
	Title: Director, Legal
William E. Macaulay
By:	/s/ Anne E. Gold
	Anne E. Gold, attorney-in-fact

[Signature page to Joint Filing Agreement with respect to Gas Natural Inc.]