The total factory overhead cost variance is

A) $2,000 favorable
B) $5,000 unfavorable
C) $2,500 unfavorable
D) $5,000 favorable

To find the total factory overhead cost variance, we need to subtract the actual overhead costs from the standard overhead costs.
Standard fixed overhead: 3 hours/unit x 2,500 units x $0.80/hour = $6,000
Actual fixed overhead: $8,000
Variance in fixed overhead = $8,000 - $6,000 = $2,000 unfavorable

Standard variable overhead: 3 hours/unit x 2,500 units x $2.00/hour = $15,000
Actual variable overhead: $18,000
Variance in variable overhead = $18,000 - $15,000 = $3,000 unfavorable

Total factory overhead cost variance = (Variance in fixed overhead) + (Variance in variable overhead)
= ($2,000 unfavorable) + ($3,000 unfavorable)
= $5,000 unfavorable.

Therefore, the best answer is B.