Correct Answer: 4, 1, 3, 2

Solution : Given:
1. Voracious 2. Voucher 3. Vortex 4. Voluntary

Step 1: Compare the first letter of each word. Since all the words start with the same letter V , then move on to the next letter.
Step 2: The second letter of each word is the same, i.e., o , then move on to the next letter.
Step 3: Compare the third letter of (Vo r acious, Vo u cher, Vo r tex, Vo l untary). Voluntary will come first as l comes before r and u in alphabetical order. Similarly, (Voracious, Vortex) will come before Voucher as u comes before r in alphabetical order.
Step 4: Compare the fourth letter of (Vor a cious, Vor t ex). Voracious will come before Vortex as a comes before t in alphabetical order.

So, the sequence is Voluntary, Voracious, Vortex, Voucher, or 4, 1, 3, 2. Hence, the third option is correct.