Dennis converted some of his household furnishings to business use during the current tax year. The original cost of the furniture was $5,000. Dennis paid $1,000 to reupholster the furniture prior to using it for business. The current FMV of the furnishings is $3,900. What is Dennis' business basis in the converted assets?

a) $5,000

b) $6,000

c) $4,900

d) $3,900