You Are Defending a Client Against a Murder Charge

You are defending a client against a murder charge. You have consulted with your client and are making preparations for the upcoming trial. The police have been searching for a weapon but have been unable to find it. This weakens the prosecution's case. Your client tells you that he was able to hide it in a wood pile in his back yard before being arrested. According to the Model Rules, your duty now is to:

A) withdraw from the case.
B) remain on the case, but alert the judge to the location of the weapon.
C) remain on the case, but require the defendant to inform the police of the weapon's location.
D) remain on the case and keep the location of the weapon confidential.