$1.$ The materials price variance is computed based on the amount of materials purchased during the period$\mathrm{.}2.$ The standard price per unit for direct materials should reflect the final, delivered cost of the materials$\mathrm{.}3.$ In general, the production manager is responsible for the materials price variance$\mathrm{.}4.$ An unfavorable materials quantity variance occurs when the actual quantity used in production is less than the standard quantity allowed for the actual output of the period.Multiple ChoiceBoth statements $1$ and $2$ are true.None of the statements are true.All of the statements are true.Both statements $2$ and $3$ are true.