C. If the tenant commits a breach that is not remediable, the landlord may serve a written notice on the tenant specifying the acts and omissions constituting the breach and stating that the rental agreement will terminate upon a date not less than 30 days after receipt of the notice. Notwithstanding anything to the contrary, when a breach of the tenant's obligations under this chapter or the rental agreement involves or constitutes a criminal or a willful act that is not remediable and that poses a threat to health or safety, the landlord may terminate the rental agreement immediately and proceed to obtain possession of the premises. For purposes of this subsection, any illegal drug activity involving a controlled substance, as used or defined by the Drug Control Act (§ 54.1-3400 et seq.), or any activity that involves or constitutes a criminal or willful act that also poses a threat to health and safety, by the tenant, an authorized occupant, or a guest or invitee of the tenant shall constitute an immediate nonremediable violation for which the landlord may proceed to terminate the tenancy without the necessity of waiting for a conviction of any criminal offense that may arise out of the same actions. In order to obtain an order of possession from a court of competent jurisdiction terminating the tenancy for illegal drug activity or for any other activity that involves or constitutes a criminal or willful act that also poses a threat to health and safety, the landlord shall prove any such violations by a preponderance of the evidence. However, where the illegal drug activity or any activity that involves or constitutes a criminal or willful act that also poses a threat to health and safety is engaged in by an authorized occupant or a guest or invitee of the tenant,