Explanation:

- "Wheat is not native to India and barley isn’t either."

- This is a correct statement. "Isn't either" effectively negates the nativity of barley to India, just like wheat.

- Correct Answer: Option: 1

- "Wheat is not native to India and barley is either."

- The phrase "is either" does not correctly follow a negative statement. It implies barley is native, which is incorrect.

- "Wheat is not native to India and barley is neither."

- This double negative would mean both are native, which is not the case.

- "Wheat is not native to India and barley isn't neither."

- Double negatives create a positive meaning, suggesting barley is native, which is incorrect.