Saran irrigation canal has been taken out from

The correct answer is: A. Son river.

The Saran canal is a branch canal of the Sone Canal, which is a major canal system in the Indian state of Bihar. The Sone Canal is a tributary of the Ganges River, and the Saran Canal is a tributary of the Sone Canal. The Saran Canal is used for irrigation and drinking water supply.

The other options are incorrect because:

• The Ganga River is a major river in India, but it is not the source of the Saran Canal.
• The Kosi River is a major river in India, but it is not the source of the Saran Canal.
• The Gandak River is a major river in India, but it is not the source of the Saran Canal.