Which of the following statements about the disposal of a factory overhead balance is true?

a$.$ An ending positive balance in the factory overhead account is disposed of by increasing Cost of Goods Sold and decreasing Factory Overhead.

b$.$ An ending negative balance in the factory overhead account is disposed of by increasing Cost of Goods Sold and increasing estimated activity base.

c$.$ An ending positive balance in the factory overhead account is disposed of by increasing Factory Overhead and decreasing estimated activity base.

d$.$ An ending negative balance in the factory overhead account is disposed of by increasing Cost of Goods Sold and decreasing Factory Overhead.