Another staff member is applying the ECG leads, but it has been about 3 minutes since the first dose of atropine was given. The patient's heart rate initially increased to 60 bpm but now is at 50 bpm. You decide to administer another dose of atropine. What dose will you give?
a) 0.5 mg
b) 1 mg
c) 2 mg
d) 3 mg