The static budget, at the beginning of the month, for Bob's Deep Sea Fishing Company follows:

Static budget:

Sales volume: $2,000$ units; Sales price: $$50\mathrm{.}00$ per unit

Variable costs: $$13\mathrm{.}00$ per unit; Fixed costs: $$25,200$ per month

Operating income: $$48,800$

Actual results, at the end of the month, follows:

Actual results:

Sales volume: $1,900$ units; Sales price: $$58\mathrm{.}50$ per unit

Variable costs: $$16\mathrm{.}5$ per unit; Fixed costs: $$33,400$ per month

Operating income: $$46,400$

Calculate the flexible budget variance for operating income.

$$3,700U$

$$16,150F$

$$3,700F$

$$1,300F$