(A) Alternate Jurors. The court may direct that 7 or more jurors be impaneled to sit in a criminal case. After the instructions to the jury have been given and the case submitted, the names of the jurors must be placed in a container and names drawn to reduce the number of jurors to 6, who shall constitute the jury. The court may retain the alternate jurors during deliberations. If the court does so, it shall instruct the alternate jurors not to discuss the case with any other person until the jury completes its deliberations and is discharged. If an alternate juror replaces a juror after the jury retires to consider its verdict, the court shall instruct the jury to begin its deliberations anew.

(B) Peremptory Challenges.

(1) Each defendant is entitled to three peremptory challenges. The prosecutor is entitled to the same number of peremptory challenges as a defendant being tried alone, or, in the case of jointly tried defendants, the total number of peremptory challenges to which all the defendants are entitled.

(2) Additional Challenges. On a showing of good cause, the court may grant one or more of the parties an increased number of peremptory challenges. The additional challenges granted by the court need not be equal for each party.