Had I read the textbook properly, I would not have failed. (simple)

• ক Without reading the textbook properly, I could not have failed.
• খ In case of having read the textbook properly, I would not have failed. ✅ সঠিক উত্তর
• গ By having read the textbook properly, I can not have failed.
• ঘ By reading the textbook properly, I would not have failed.