The Greatest Development in the Kushana Period was in the Field of
option 2 is the right answer.
The Kushan Empire was an empire originally formed in the early 1st century CE under Kujula Kadphises in the territories of the former Greco-Bactrian Kingdom around the Oxus River later reached their peak under the Buddhist emperor Kanishka the Great (127–151), whose realm stretched from Turfan in the Tarim Basin to Pataliputra on the Gangetic Plain.
The art and culture of Kushans, at the crossroads of the Kushan hegemony, continued the traditions of Greco-Buddhist art and are the best known expressions of Kushan influences to Westerners. Several direct depictions of Kushans are known from Gandhara,
where they are represented with a tunic, belt and trousers and play the role of devotees to the Buddha, as well as the Bodhisattva and future Buddha Maitreya.