You have been called to an office building for a 47-year-old male complaining of chest pain. He is alert, oriented, and complaining of pain in his chest that came on suddenly about 15 minutes ago. His skin is diaphoretic and cool. Which one of the following should you do first?

A) Apply supplemental oxygen through a nasal cannula.
B) Obtain a heart rate, respiratory rate, blood pressure, and SpO2 reading.
C) Determine if there is a family history of cardiac illness.
D) Administer the first of up to three nitroglycerin tablets.

B