If 1st January, 2001 was Monday, then what day of the week was it on 31st December, 2001?

Correct option is D

Step 1: Check leap year or not

Year = 2001.

Divisible by 4?  (2001 ÷ 4 = remainder).

So, 2001 is not a leap year → 365 days.

Step 2: Extra days in 2001

365 days = 52 weeks + 1 extra day.

So, every date will shift forward by 1 day.

Step 3: Day on 31st December 2001

1st January 2001 = Monday.

After 364 days (which is 52 weeks), it will again be Monday (on 31st December).

So, 31st December 2001 was Monday.

Final Answer: (D) Monday