A. Except as provided in section 25-501, subsection F, any parent of a minor child who knowingly fails to furnish reasonable support for the parent’s child is guilty of a class 6 felony.

B. It is an affirmative defense to a charge of a violation of subsection A of this section that the defendant has complied with a valid court order that was in effect for the time period charged and that set forth an amount of support for the minor child or was unable to furnish reasonable support. Inability to furnish reasonable support is not a defense if the defendant voluntarily remained idle, voluntarily decreased his income or voluntarily incurred other financial obligations.

C. The trier of fact, in determining whether the defendant has failed to furnish reasonable support, shall consider all assets, earnings and entitlements of the defendant and whether the defendant has made all reasonable efforts to obtain the necessary funds. On a showing of previous employment or lack of a physical or mental disability precluding employment, the trier of fact may infer that the defendant is capable of full-time employment at least at the federal adult minimum wage. This inference does not apply to noncustodial parents who are under the age of eighteen and who are still attending high school.