If 28 May 2015 is Thursday, then what will be the day of the week on 24 April 2023?

Correct option is C

An ordinary year has 1 odd day and a leap year has 2 odd days. 
If 28 May 2015 is Thursday,
28 May 2016 – Saturday (leap year)
​28 May 2017 – Sunday
​28 May 2018 – Monday
​28 May 2019 – Tuesday
​28 May 2020 – Thursday
​28 May 2021 – Friday
​28 May 2022 – Saturday
​28 May 2023 – Sunday
Number of days between 24 April 2023 to ​28 May 2023 = (6 + 28) = 34
34 when divided by 7, leaves 6 as remainder.
Sunday - 6 = Monday
Therefore, it will be Monday on 28 May 2023.