Sentence:  If a taxpayer dies , the executor , administrator , or legal representative must file the final return for the decedent on or before the 15 th day of the 4 th month following the close of the deceased taxpayer 's <WSD>normal</WSD> tax year . 
Meaning of the word marked with <WSD> tags:  conforming with or constituting a norm or standard or level or type or social norm; not abnormal