When a crime is into degrees, what is the test for determining whether a defendant is guilty of first degree murder?

When a crime is divided into degrees, the jury must find the degree of the crime. ( 1157.) It is settled, however that in a prosecution for first degree murder it is not necessary that all jurors agree on one or more of several theories proposed by the prosecution; it is sufficient that each juror is convinced beyond a reasonable doubt that the defendant is guilty of first degree murder as that offenses is defined by statute. ( People v. Milan (1973) 9 Cal.3d 185, 195[107 Cal.Rptr. 68, 507 P.2d 956].) ( People v. Guerra (1985) 40 Cal.3d 377, 386, 220 Cal.Rptr. 374, 708 P.2d 1252; accord,

[221 Cal.App.4th 1025]

People v. Moore (2011) 51 Cal.4th 386, 413, 121 Cal.Rptr.3d 280, 247 P.3d 515; People v. Millwee (1998) 18 Cal.4th 96, 160, 74 Cal.Rptr.2d 418, 954 P.2d 990.) We have no quarrel with this principle of law, cited by the Attorney General, but the rule has no application in this case because there was only one theory of first degree murder.