Correct Answer: 1, 4, 5, 3, 2

Solution : Given:
1. Organ 2. Origin 3. Orient 4. Organic 5. Organise

Step 1: Since all the words start with the same letter O , so move on to the next letter.
Step 2: The second letter of each word is the same, i.e., r . So, move on to the next letter.
Step 3: The third letter of each word is either g or i . The arrangement can be – (Organ, Organic, Organise), (Origin, Orient) as g comes before i according to the alphabetical system.
Step 4: The fourth, and fifth letters of (Org an , Org an ic, and Org an ise) are the same, i.e., a , and n . Organ will come before Organic and Organise as all the letters of the word Organ lie in the word Organic, and Organise and it has less number of letters.
Step 5: The sixth letter of (Organ i c, Organ i se) is the same. So, move on to the next letter.
Step 6: Compare the seventh letter of (Organi c , Organi s e). Organic will come before Organise as c comes before s according to the alphabetical system.
Step 7: Compare the fourth letter of (Ori g in, Ori e nt). Orient will come before Origin as e comes before g according to the alphabetical system.

So, the sequence is Organ, Organic, Organise, Orient, Origin, or 1, 4, 5, 3, 2. Hence, the third option is correct.