Which of the following statement(s) is/are found to be incorrect? I. The two schools of art that flourished during the Post-Mauryan era are the Gandhara School (also known as the Greeko Buddhist School) and the Amravati School. II. The Gandhara School was established in the lower valley of Krishna and Godavari during the second century BC, in the later Satavahana period. III. The Indo Greeks were the first rulers to issue gold coins in India and introduced features of Hellenistic art in the North Western frontier of India.