The phonetic morphological and syntactic systems undergo serious changes in the Russian language from the XIV to XVII century. How is this period called? Choose ONE correct answer. Old Russian Novorussian Protorussian Ancient Russian

The correct answer is: Old Russian.<br /><br />During the period from the XIV to XVII century, the Russian language underwent significant changes in its phonetic, morphological, and syntactic systems. This period is referred to as the Old Russian period. The other options, Novorussian, Protorussian, and Ancient Russian, are not accurate terms for this specific time frame in the development of the Russian language.