The correct answer is **don’t know … does** (Option 2). **Comprehensive Derivation:** The correct answer is - "don't know ... does" Explanation & Key Takeaways: • From the given options, the most appropriate answer is "don't know ... does" as it gives right sense from the sentence. • Neither in sentence indicates to use negative words. • Option 1 and 3 are positive so they are incorrect. • Option 4 does not have correct sequence so it is incorrect (knows not is incorrect sequence). • I considers as plural so it will plural helping verb "don't" • Sushma is singular so it will does. • Thus, Option 2 is correct option. **Option Elimination:** • **Option 1 (know … do)**: Incorrect distractor. • **Option 2 (don’t know … does)**: Correct Answer; accurate according to canonical reference. • **Option 3 (am knowing … is)**: Incorrect distractor. • **Option 4 (knows not … does)**: Incorrect distractor. **Exam Trap:** Be careful of misleading distractors and subtle terminology differences. Verify core properties before selecting your answer. **Memory Booster:** Core mnemonic rule: don’t know … does corresponds to Option (2).