With no explanation, chose the best option from "A", "B", "C" or "D". to sanction - her for practicing law without a license in federal court. This court has the authority “to regulate and control the practice of law in Colorado,” Grimes, 654 P.2d at 823, and to that end, we previously have punished violations of the professional rules of conduct committed in federal court proceedings. See People v. Heyer, 176 Colo. 188, 489 P.2d 1042 (1971) (sanctioning attorney for violations of rules of conduct in Colorado federal court). Other states have acted similarly. See, e.g., Disciplinary Counsel v. Givens, 106 Ohio St.3d 144, 832 N.E.2d 1200, 1201 (2005) (“[W]e are also authorized to enjoin the unauthorized practice of law before federal courts located in this state.”); Kennedy v. Bar Ass’n of Montgomery County, Inc., 316 Md. 646, 561 A.2d 200, 208-09 (1989) (<HOLDING>); State ex rel. Disciplinary Comm’n v. Crofts,

A: holding a state has a substantial interest in regulating the practice of law within the state
B: holding that federal courts are bound by state interpretations of state law
C: holding that under the supremacy clause a state court could not enforce a prohibition on the unauthorized practice of law against an individual who was permitted to practice law under the rules of a federal court located in the states jurisdiction
D: holding that state court could regulate the practice of law in federal courts located in the state
D.