Task: Text Completion
Input (English): 17-18. Little progress has therefore been made in either action. Thus,- this factor weighs against abstention or is neutral at best. Similarly, the seventh factor—“the relative progress of the state and federal proceedings”—does not favor abstention because neither case has progressed into discovery. See R. 7-1 at 24 (noting that the state court denied the plaintiffs’ motion to dismiss, but not noting that discovery had begun); see also R. 7-2 (state-court record). Randy argues that the fifth factor—“whether the source of governing law is state or federal”—supports abstention because he challenges the validity of the arbitration agreement by raising a contractual defense. R. 7-1 at 24; see First Options of Chi., Inc. v. Kaplan, 514 U.S. 938, 944, 115 S.Ct. 1920, 131 L.Ed.2d 985 (1995) (<HOLDING>). Federal law, however, provides the rule of 
 Holding statements: (A) holding that the court was not bound by the parties agreement that contracts were unambiguous and holding that contracts were ambiguous (B) holding that the essential inquiry in determining whether res judicata principles should apply is whether or not the ultimate and controlling issues have been decided in a prior proceeding in which the present parties had an opportunity to appear and assert their rights (C) holding that equitable principles apply to child support proceedings (D) holding that when deciding whether parties have agreed to arbitrate claims courts generally  should apply statelaw principles that govern the formation of contracts (E) holding that equitable tolling principles apply to suits against the united states in the same manner as they apply to private parties
Output (English): (D)