Which of the following definitions used in accounting for income taxes is least accurate （）

A. An income tax expense is an expense resulting from current period pretax income and change in deferred taxes. 

B. A valuation allowance is a reserve against deferred tax assets based on the likelihood that those assets will not be realized.  

C. A deferred tax liability is a balance sheet amount related to the difference between tax expense and taxes payable that is expected to be recovered from future operations