The largest item of the Deferred Tax Liability for most companies is caused by$?$

$1.$providing the allowance for doubtful accounts for book purposes.

$2.$differences in inventory cost flow assumptions $($FIFO vs$.$ LIFO$)$ for tax versus financial accounting purposes.

$3.$differences in depreciation methods $($accelerated vs$.$ straight$-$line$)$ for tax versus financial accounting purposes.

$4.$amortizing bond premium or discount for tax purposes.