Correct Answer: Sunday

Solution : Code for months –

Code for days –

Code for centuries –

For, 10th of October 2021 –
Formula: {Date + (Month code) + (Century code) + ( last two digit of the year) + ((last two digit of the year / 4)'s Quotient)} / 7

Date = 10
Code for the month (October) = 0
Code for the century (2000) = 6
(2021 = 2000 + 21; For 2000 it will be 6 and for 21 it will be 21)
And, 21 ÷ 4 = 5(Quotient)
Now, on adding them we get→10 + 0 + 6 + 21 + 5 = 42
On dividing 42 by 7, we get 0 as a remainder.
0 is the code for Sunday.

So, the 10th of October 2021 will be Sunday. Hence, the second option is correct.