Read the following excerpt from a US court opinion:
```
damages; and (6) the risk of duplicative recoveries or complex apportionment of damages. Balaklaw, 14 F.3d at 797 n. 9 (citing Associated Gen. Contractors of Cal., Inc., 459 U.S. at 537-45, 103 S.Ct. 897). In the context of health care antitrust litigation, courts have observed that physicians may not be the most efficient enforcer of the antitrust laws. See, e.g., Daniel, 428 F.3d at 443-44 (concluding that physician-plaintiffs seeking to join cartel were not efficient enforcers of antitrust laws); Korshin v. Benedictine Hosp., 34 F.Supp.2d 133, 140-41 (N.D.N.Y.1999). Nevertheless, where a physician’s interest coincides with the patient’s interest, a physician may be a proper enforcer of the antitrust laws. See Angelico v. Lehigh Valley Hosp., Inc., 184 F.3d 268, 274-75 (3d Cir.1999) ; Nilavar v. Mercy Health Sys.-W. Ohio, 142
```
What is the most suitable continuation to the opinion? Your options are:
A. holding that an activity which is exempt from the antitrust laws cannot form the basis of an antitrust investigation
B. holding that a plaintiff must show antitrust injury in order to bring an antitrust lawsuit
C. holding that plaintiffphysician was efficient enforcer of antitrust laws
D. holding that there must be a causal connection between the alleged antitrust violation and the antitrust injury for there to be antitrust standing
E. holding that the fcc was not given the power to decide antitrust issues and that its actions do not prevent enforcement of the antitrust laws in federal courts
Reply with [A, B, C, D, E] only.