In a stable system, over the long run, the rate out of a system will equal the rate in$,$ less any yield loss, plus any parts production within the system. Which Law does it refer to$?$

Choice $1$ of $4$: Law $($Conservation of Material$)$

Choice $2$ of $4$: Law $($Capacity$)$

Choice $3$ of $4$: Law $($Variability Buffering$)$

Choice $4$ of $4$: Law $($Move Batching$)$