Concept:The last day of a year is found by counting the total odd days from a reference point (1 AD) up to that date. Each odd day shifts the weekday forward by one.
Explanation:Step 1: Find odd days up to the year 1800.
1600 years give 0 odd days. The next 200 years (1601 to 1800) give 3 odd days.
So total odd days up to 1800 = 0 + 3 = 3.
Step 2: Calculate odd days for years 1801 to 1856 (56 years).
Leap years in 56 years = 56 ÷ 4 = 14.
Ordinary years = 56 − 14 = 42.
Odd days = (14 × 2) + (42 × 1) = 28 + 42 = 70.
70 ÷ 7 leaves remainder 0. So 0 odd days.
Step 3: For the target year 1857, we need December 31. 1857 is an ordinary year (365 days).
365 days = 52 weeks + 1 odd day. So 1 odd day.
Step 4: Add all odd days.
Total = 3 (from 1800 years) + 0 (from 1801–1856) + 1 (from 1857) = 4 odd days.
Use the mapping: 0 = Sunday, 1 = Monday, 2 = Tuesday, 3 = Wednesday, 4 = Thursday.
Thus, the last day of 1857 is Thursday.
Answer:Option A. Thursday