Indicate whether the following items are a $($a$)$ change in accounting principle, $($b$)$ change in accounting estimate,

$($c$)$ change in reporting entity, or $($d$)$ correction of an error.

The salvage value of a building being depreciated over $30$ years is adjusted from $$15,000$ to $$5,000$ due to the unexpected deterioration of the building.

A company discovered that depreciation expense was overstated by $$50,000$ in the prior year's financial statements due to incorrect asset valuation amounts entered into the fixed asset depreciation software.

A company changes its depreciation method from the straight$-$line method to the double$-$declining balance method for the long$-$term asset category of equipment.