A business operated at $100\%$ of capacity during its first month and incurred the following costs:

Production costs $(5,000$ units$)$:

Direct materials $$70,000$

Direct labor $20,000$

Variable factory overhead $10,000$

Fixed factory overhead $2,000$ $$102,000$

Operating expenses:

Variable operating expenses $$17,000$

Fixed operating expenses $1,00018,000$

If $1,000$ units remain unsold at the end of the month and sales total $$150,000$ for the month, the amount of contribution margin that would be reported on the variable costing income statement is

a$.$ $$54,000$

b$.$ $$51,400$

c$.$ $$52,000$

d$.$ $$53,000$