Donner United has total owners' equity of $$18,800.$ The firm has current assets of $$23,100,$ current liabilities of $$12,200,$ and total assets of $$36,400.$ What is the value of the long$-$term debt?

a$.$ $$5,400$

b$.$ $$29,800$

c$.$ $$12,500$

d$.$ $$13,700$

e$.$ $$43,000$