Final answer:
To find the day of the week for Arun's sister's birthday, we calculate the number of days between May 25 and July 13 and determine the remainder when dividing by 7. The remainder tells us the number of extra days. By counting from Monday, the extra days bring us to D)Saturday.
Step-by-step explanation:
To determine the day of the week for Arun's sister's birthday, we first need to find out the number of days between May 25 and July 13. Assuming that both May and July have 31 days, we have 31 - 25 = 6 days in May and 13 days in July. This gives us a total of 6 + 13 = 19 days.
Since there are 7 days in a week, we divide 19 by 7. The remainder of 5 tells us that there are 5 extra days.
Starting from Monday, we count 5 days ahead, which brings us to Saturday. Therefore, Arun's sister's birthday falls on Saturday.