What is the expected date of delivery for the woman who has had their last menstrual period on April 20th.. January 27th

What is the expected date of delivery for the woman who has had their last menstrual period on April 20th?
A- January 20th
B- January 27th
C- January 29th
D- January 31st

Correct Response: B

According to Nagle’s rule, this estimated date of delivery is calculated as below:
The First Day of the Last Menstrual Period: April 20th
Subtract 3 Months: January 20th
Add 7 Days: January 20th plus 7 days = January 27th
Estimated Date of Delivery: January 27th of the following year