Regarding questions concerning the admissibility of evidence, the questions must in every case be left largely to the sound discretion of the trial court, subject to review only in case of manifest abuse. Watkins v. Williams, 265 Mont. 306, 311, 877 P.2d 19, 21-22 (1994) (citation omitted).
We generally review a district court's evidentiary rulings for an abuse of discretion. A district court abuses its discretion if it acts arbitrarily without the employment of conscientious judgment or exceeds the bounds of reason, resulting in substantial injustice. Notwithstanding this deferential standard, however, judicial discretion must be guided by the rules and principles of law; thus, our standard of review is plenary to the extent that a discretionary ruling is based on a conclusion of law. In such circumstance, we must determine whether the court correctly interpreted the law. State v. McOmber, 2007 MT 340, ¶ 10, 340 Mont. 262, 173 P.3d 690 (citations and quotation marks omitted).