QRS Ltd has the following standard cost data for one unit of its product:

Direct materials: 6 kg at $3 per kg

Direct labor: 4 hours at $10 per hour

Variable overhead: 4 hours at $4 per hour

Actual data for the month of April 2025 is as follows:

Units produced: 4,000 units

Direct materials used: 24,500 kg at $2.80 per kg

Direct labor: 16,500 hours at $9.50 per hour

Actual variable overhead: $64,000

Required: a. Calculate the direct material price variance and direct material usage variance. b. Calculate the direct labor rate variance and direct labor efficiency variance. c. Calculate the variable overhead spending and efficiency variances. d. Analyze the variances and provide possible explanations for the differences.