Correct Answer: 4, 2, 5, 1, 6, 3

Solution : Given:
1. Circulate 2. Circuit 3. Citrus 4. Cinnamon 5. Circular 6. Citizens

Step 1: The first and second letters of each word are the same, so move on to the next letter.
Step 2: The third letter of each word is: r , r, t , n, r, t . Based on the alphabetical order of these letters, we can arrange them: Ci n namon, Ci r culate, Ci r cuit, Ci r cular, Ci t rus, Ci t izens
Step 3: Compare the sixth letter of (Circu l ate, Circu i t, Circu l ar) and the fourth letter of (Cit r us, Cit i zens). Circuit will come before Circular and Circulate in the sequence as i comes before l in the alphabetical system. Similarly, Citizens will come before Citrus as i will come before r .
Step 4: Compare the eighth letter of (Circula t e, Circula r ). Circular will come before Circulate in the sequence as r comes before t in the alphabetical system.

So, the sequence is Cinnamon, Circuit, Circular, Circulate, Citizens, Citrus, or 4, 2, 5, 1, 6, 3. Hence, the fourth option is correct.