Which statements correctly define tachycardia and bradycardia thresholds?

• A. Tachycardia: heart rate greater than 100 beats per minute; Bradycardia: heart rate less than 60 beats per minute.
• B. Tachycardia: HR greater than 90; Bradycardia: HR less than 50.
• C. Tachycardia: HR greater than 110; Bradycardia: HR less than 70.
• D. Tachycardia: HR greater than 100; Bradycardia: HR less than 50.

Answer: (A)