In September, Larson Inc. sold 48,000 units of its only product for $372,000, and incurred a total cost of $345,000, of which $37,000 was fixed costs. The flexible budget for September showed total sales of $420,000. Among variances of the period were: total variable cost flexible-budget variance, $8,000U; total flexible-budget variance, $72,000U; and, sales volume variance, in terms of contribution margin, $39,000U.

The sales volume variance, in terms of operating income, for September (to the nearest dollar) was: