$(18)$ The formula for the direct materials $($DM$)$ price variance is

A$)(A{Q}_{\text{p}\text{u}\text{r}\text{c}\text{h}}AP)-(A{Q}_{\text{p}\text{u}\text{r}\text{c}\text{h}}SP).$

B$)$ purch $SP.$

C$)$ purch $SP.$

D$)$ purch $SP.$