Explanation:

To determine the day of the week for 30 December 2015, given that 28 February 2020 was Friday, follow these steps:

- Calculate the total number of days between the two dates.

- 2020 is a leap year with 366 days. Hence, the days from 29 February 2020 to 28 February 2016 should be - 365 + 1 = 366 (due to the extra day in February for a leap year).

- Years 2019, 2018, 2017: 3 non-leap years with 365 days each = 3 * 365 = 1095.

- Days from the end of 2015 to 30 December 2015:

- From 31 December 2015 back to 1 in 30 December 2015: \( 31 - 30 = 1 \) day.

Now, add them up: 366 (leap year offset) + 1095 (three years) + 1 = 1462.

Next, divide 1462 by 7 to get the number of weeks and additional days:

- 1462 ÷ 7 = 208 weeks and 6 additional days.

If 28 February 2020 was Friday, then 6 days before would be:

- Thursday, Wednesday, Tuesday, Monday, Sunday, Saturday.

30 December 2015 was a Wednesday.

- Option 1 – Wednesday