Which of the following kings introduced the Saka era?

Kanishka

The correct answer is Option 3- Kanishka

The Saka era is a historical era that begins with the accession of Kanishka to the throne of the Kushan Empire in 78 CE. It is based on the Saka calendar, which was a solar calendar used by the Saka peoples of Central Asia.

Kanishka was the fourth emperor of the Kushan Empire, which ruled over much of Central Asia and northwestern India from the 1st to the 3rd centuries CE. He was a great patron of Buddhism and the arts, and his reign is considered to be a golden age of Indian culture.

The Saka era was introduced by Kanishka in order to unify the various calendars that were used in his empire. It quickly became the standard calendar in much of Central Asia and northwestern India, and it is still used by some communities in these regions today.