Alcott Industries manufactures a specialized electronic component with the following standard costs:

Standard Quantity or Hours

Standard Price or Rate

Direct materials

$5\mathrm{.}30$

grams

$ $2\mathrm{.}80$

per gram

Direct labor

$0\mathrm{.}40$

hours

$ $29\mathrm{.}00$

per hour

Variable overhead

$0\mathrm{.}40$

hours

$ $3\mathrm{.}80$

per hour

The company reported the following results concerning this product in July.

Actual output

$4,800$

units

Raw materials used in production

$13,170$

grams

Actual direct labor$-$hours

$1,700$

hours

Purchases of raw materials

$13,900$

grams

Actual price of raw materials purchased

$ $3\mathrm{.}00$

per gram

Actual direct labor rate

$ $13\mathrm{.}20$

per hour

Actual variable overhead rate

$ $3\mathrm{.}90$

per hour

Variable overhead is allocated based on direct labor$-$hours at Alcott Industries. The variance for direct material purchases is calculated at the time of acquisition. The variable overhead efficiency variance for July is::

Group of answer choices

a$.$ $$836$ F

b$.$ $$858$ U

c$.$ $$858$ F

d$.$ $$836$ U