Which of the following statements alone is sufficient to answer the question.

The monthly incomes of friends Amitabh, Abhishek, and Aishwarya are in the ratio 6:5:4. Amitabh's expenditure is Rs. 12,000, which is 80% of Abhshek's expenditure. Aishwarya spends 40% of his income. Amitabh initiates a business by investing 50% of his monthly savings. After a while, Abhhishek and Aishwarya  join him, investing 80% and 50% of their monthly savings, respectively. After some additional months, Amitabh exits the partnership. The final profits received by Amitabh, Abhishek, and Aishwarya are in the ratio 45:32:24.

What is the period of investment of Amitabh?

Which of the following statement(s) alone is sufficient to find the answer?

I. Aishwarya invested for a total 16 months.

II. Abhhishek invested for 4 months less than Amitabh.

III. The investment period of Amitabh and Aishwarya are in the ratio 5: 4 respectively.

IV. Monthly income of Abhishek is Rs.25000.

V. The total period of partnership is 24 months.