Which of the following statements is true?

a$.$ A company can increase the book value of a component to an amount higher than the component's book value before it was classified as held for sale.

b$.$ A company reports any pre$-$tax gain $($loss$)$ from the sale of a held$-$for$-$sale component in the results from discontinued operations of its income statement.

c$.$ After a company writes down a held$-$for$-$sale component to fair value, there may be no subsequent changes in fair value.

d$.$ When a company completes the sale of a held$-$for$-$sale component, it computes any additional gain $($loss$)$ on the sale by subtracting the adjusted net book value of the component from the net proceeds received.