Kirk Manufacturing Co. uses normal costing in its job-costing system. At the beginning of April, Kirk only had one job in process, Job #898. This job was finished during April by incurring additional direct costs of $350 for materials and $700 for manufacturing labor. Also during April, Job #899 was started and finished. The direct costs assigned to this job were $1,200 for materials and $950 for manufacturing labor. Job #900 was started during April but was not finished by the end of the month. The direct costs assigned to this job were $820 for materials and $540 for manufacturing labor. Kirk allocates manufacturing overhead to its products at a rate of 200% of direct manufacturing labor cost. Kirks cost of goods manufactured for April was $14,570. What was Kirks work-in-process inventory balance at the beginning of April?

a. $10,010

b. $6,420

c. $8,070

d. $11,370

e. $5,630