With no explanation, chose the best option from "A", "B", "C" or "D". containing the arbitration clause].” Id. The HMOs nonetheless direct our attention to more general language from MS Dealer, which notes that equitable estoppel may be appropriate “when the signatory [to the contract containing the arbitration clause] raises allegations of ... substantially interdependent and concerted misconduct by both the nonsignatory and one or more of the signatories to the contract.” Id. (quoting Boyd at 1433). The HMOs contend that this language mandates an application of equitable estoppel in this case simply because the doctors allege a RICO conspiracy. This contention is only tenable if the passage is read completely out of context. MS Dealer “is not a rigid test, and each case turns on its facts.” Hill v. G E Power Systems, Inc., 282 F.3d 343 (5th Cir.2002) (<HOLDING>). In all cases, “‘the lynchpin for equitable

A: holding district court did not abuse its discretion in not granting plaintiffs leave to amend complaint for a third time
B: holding that district court did not abuse its discretion in declining to extend time for service of process under rule 4m
C: holding that district court did not abuse its discretion in declining to apply doctrine of equitable estoppel even though complaint alleged collusive scheme to defraud
D: holding that the district court did not abuse its discretion in declining to apply laches where the only prejudice shown by the government was attributable to its own delay rather than to that of the movant
C.