Pay and discharge (a) all Taxes prior to the date on which they become delinquent or penalties attach, unless such Taxes are being Properly Contested; (b) all lawful claims which, if unpaid, would by law become a Lien upon its Property; and (c) all Indebtedness, as and when due and payable, but subject to any subordination provisions contained in any instrument or agreement evidencing such Indebtedness.