Which of the following is the most probable reason a company would experience an unfavorable labor rate variance and a favorable labor efficiency variance?

• Defective materials caused more labor to be used in order to produce a standard unit.
• The mix of workers assigned to the particular job was heavily weighted towards the use of new relatively low paid unskilled workers.
• Because of the production schedule, workers from other production areas were assigned to assist this particular process.
• The mix of workers assigned to the particular job was heavily weighted towards the use of higher paid experienced individuals.