For Early Detection of an Anaphylactic Reaction in a Patient

For early detection of an anaphylactic reaction in a patient who has received allergen testing using the cutaneous scratch method, which action should the nurse take first?

A) Check blood pressure and pulse rate.
B) Auscultate the lung sounds bilaterally.
C) Monitor pupil size and reaction to light.
D) Assess the arm at the site of the skin testing.