Gandhara Art' is primarily influenced by the Greek regional style, particularly the Hellenistic style. 

Gandhara Art emerged in the region of Gandhara (now in modern-day Pakistan and Afghanistan) during the first few centuries CE. It was a unique blend of Indian, Persian, and Greek artistic traditions and was particularly influenced by the artistic elements and styles introduced by the Greek rulers in the region following the conquests of Alexander the Great. Greek artistic features, such as realistic depictions of the human form and drapery, are evident in Gandhara Art, making it one of the distinctive characteristics of this art style.

So, the correct answer is option 2: Greek.