AMM developed a standard usage of $3$ pounds of materials @ $$1\mathrm{.}50,$ for each unit produced. AMM's initial inventory of finished units for the month was $5,000$ pounds of materials, and it purchased an additional $15,000$ pounds for $$19,500.$ The company produced $5,000$ units during the month. Based on this data, we can say that the price and usage $($efficiency$)$ variations, respectively, are as follows

Price variation Usage variation

a$.$

$$3,000$ favorable; $$1,500$ unfavorable.

b$.$

$$3,000$ unfavorable; $$1,500$ favorable

c$.$

$$3,000$ favorable; $$0$

d$.$

$$3,200$ favorable; $$1,500$ unfavorable