When asked, a young female with abdominal pain replies that she is not sure if she is pregnant or not. Which one of the following questions provides the best opportunity to determine if the patient is pregnant?

A) "Do you feel pressure in your belly area?"
B) "When was your last menstrual period?"
C) "Have you been vomiting in the morning?"
D) "Does it feel like the last time you were pregnant?"

B