Trini Company set the following standard costs per unit for its single product

Direct materials $(30$ pounds @ $$4\mathrm{.}80$ per pound$)$ $ $144\mathrm{.}00$

Direct labor $(6$ hours @ $$14$ per hour$)84\mathrm{.}00$

Variable overhead $(6$ hours @ $$7$ per hour$)42\mathrm{.}00$

Fixed overhead $(6$ hours @ $$9$ per hour$)54\mathrm{.}00$

Standard cost per unit $ $324\mathrm{.}00$

Overhead is applied using direct labor hours. The standard overhead rate is based on a predicted activity level of $80\%$ of the company$$s capacity of $57,000$ units per quarter. The following additional information is available.

Operating Levels

$70\%80\%90\%$

Production $($in units$)39,90045,60051,300$

Standard direct labor hours $(6$ DLH per unit$)239,400273,600307,800$

Budgeted overhead $($flexible budget$)$

Fixed overhead $ $2,462,400$ $ $2,462,400$ $ $2,462,400$

Variable overhead $ $1,675,800$ $ $1,915,200$ $ $2,154,600$

During the current quarter, the company operated at $90\%$ of capacity and produced $51,300$ units; actual direct labor totaled $304,800$ hours. Units produced were assigned the following standard costs.

Direct materials $(1,539,000$ pounds @ $$4\mathrm{.}80$ per pound$)$ $ $7,387,200$

Direct labor $(307,800$ hours @ $$14$ per hour$)4,309,200$

Overhead $(307,800$ hours @ $$16$ per hour$)4,924,800$

Standard $($budgeted$)$ cost $ $16,621,200$

Actual costs incurred during the current quarter follow.

Direct materials $(1,519,000$ pounds @ $$7\mathrm{.}30$ per pound$)$ $ $11,088,700$

Direct labor $(304,800$ hours @ $$13\mathrm{.}00$ per hour$)3,962,400$

Fixed overhead $2,337,000$

Variable overhead $2,187,800$

Actual cost $ $19,575,900$

Required:

$($a$)$ Compute the variable overhead spending and efficiency variances.

$($b$)$ Compute the fixed overhead spending and volume variances.

$($c$)$ Compute the overhead controllable variance.