Explanation:

- She was so (a): This part is grammatically correct. "She was so" sets up a phrase that likely describes a high degree or extent of something.

- Near (b): This is correct. "Near" here is used as a modifier suggesting she was close to achieving her goal.

- Achieving her goal. (c): This is also correct. It clearly states the objective she was close to reaching.

- No Error (d): This option suggests that the sentence is grammatically correct as it is.

The sentence "She was so near achieving her goal" is correctly structured with no grammatical mistakes.

- The correct answer is: Option 4, d