登录之后可查看解析

Answer (B) is correct . An unfavorable material efficiency variance means that excess materials were used during production. This might be due to buying inferior quality materials or using workers who were not as skilled in working with the materials. Also, new equipment might damage materials during early production runs.

Answer (A) is incorrect because Inferior raw materials can be a cause of an unfavorable materials efficiency variance.
Answer (C) is incorrect because Less-skilled workers can tend to be wasteful of raw materials, leading to an unfavorable efficiency variance.
Answer (D) is incorrect because The use of unfamiliar equipment can result in an unfavorable materials efficiency variance.