Explanation:

- Initial Scenario:

- 12 women can make 15 toys in 6 days.

- They work 8 hours a day.

- Analysis:

- Total hours of work = 12 women x 6 days x 8 hours = 576 woman-hours for 15 toys.

- For 1 toy, hours required = 576 / 15 = 38.4 woman-hours.

- New Scenario:

- 20 toys to be made by 10 women.

- Working 12 hours a day.

- Calculation:

- Total woman-hours required for 20 toys = 20 x 38.4 = 768 woman-hours.

- Woman-hours per day = 10 women x 12 hours = 120 woman-hours per day.

- Days required = 768 / 120 = 6.4 days.

- Conclusion:

- Option 3: 6.4 days