Answer:
The correct answer is (b).
Step-by-step explanation:
Pacemakers are small metal boxes implanted in the thorax cavity to help control abnormal heart rhythms. This device uses electrical pulses to prompt the heart to beat at a normal rate.
Batteries are included in the small box and do not need open heart surgery to get them replaced.
Usually, they are made of lithium, and the expected lifetime is from 7 to 10 years.
Replacing a pacemaker is a simple surgery that may take no more than 30 minutes.
I hope it helps!