The given calendar date is 28 May 2007 Now, follow the steps to calculate the day on 28 May 2007. 1) Take the last 2 digits of the year i.e. '07' 2) Divide it by 4 and neglect the remainder. ⇒ 07 ÷ 4 = 01 (Don't take decimal values and remainder) Here, the remainder is 3, neglect it. 3) Add the day of the month in the value obtained from the previous step. ⇒ 01 + 28 = 29 4) Our month is May which has a key value of 2. Add the key value to the value obtained from the previous step. ⇒ 29 + 02 = 31 5) Add the year code for the century in the previous value. Year code for the century 2000 is 6. ⇒ 31 + 06 = 37 6) Add the last two digits of the year in the previous value. ⇒ 37 + 07 = 44 7) Divide this value by 7 and take the remainder. ⇒ 44 ÷ 07 = 06 and the remainder is 02. The day based on the value of the remainder 02 will be Monday. Therefore, there was a Monday on 28 May 2007. Hence, the correct answer is Monday.