Is the jury instructed on two theories of second degree murder?

The jury was instructed on two theories of second degree murder: felony murder and implied malice. Instruction on the felony-murder theory constituted prejudicial error requiring reversal of appellants' convictions of second degree murder, because it cannot be determined whether the jury reached its verdict based upon a theory of implied malice, as to which we will find appellants contentions on appeal unmeritorious, . or felony murder. (People v. Smith, supra, 35 Cal.3d 798, 808, 201 Cal.Rptr. 311, 678 P.2d 886.)