Explanation:

- Option 1: Kadphises in 58 BC

- Kadphises was a Kushan ruler but did not start the Saka era.

- The Saka era is not associated with 58 BC.

- Option 2: Rudradaman 1 in 78 AD

- Rudradaman was a Satrap ruler, but he didn't start the Saka era.

- The date 78 AD is significant but not linked to Rudradaman.

- Option 3: Vikramaditya in 58 BC

- Vikramaditya is traditionally linked to the Vikrama Samvat, starting in 58 BC.

- It's not the same as the Saka era.

- Option 4: Kanishka in 78 AD

- This is a common misconception.

- Kanishka started his own era in 78 AD, not the Saka era.

- Correct Answer: Option 2: Rudradaman 1 in 78 AD

- The correct starter of the Saka era is not listed in the options, but it is believed to be linked to an Indo-Scythian, ruling during 78 AD.

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