On January 1, 2017, Petersen Corp. sold a piece of equipment for $3,000 which it had used for several years. The equipment had cost $13,000, and its accumulated depreciation amounted to $9,000 at the time of the sale. What are the net effects on the accounting equation of selling the equipment?

a.Assets decrease and Stockholders' Equity increases $3,000.

b.Assets and Stockholders' Equity decrease $1,000.

c.Assets and Stockholders' Equity decrease $3,000.

d.Assets and Stockholders' Equity increases $1,000.