Final answer:
The correct energy dose for unstable atrial fibrillation when delivering monophasic synchronized shocks is 100 J, sufficient for cardioversion without excess tissue damage.
Step-by-step explanation:
The correct energy dose for delivering monophasic synchronized shocks in the case of unstable atrial fibrillation would typically be option B) 100 J. Synchronized cardioversion is used in unstable patients who display a rapid heartbeat that has not responded to medical therapy, and the amount of energy needs to be sufficient to reset the heart's rhythm without causing unnecessary damage.
Relevant to the topic, when defibrillators are used during medical procedures, they often deliver a significant amount of energy measured in SI units of joules. The energy dissipates in the body and is critical for restoring normal heartbeats during instances of arrhythmias or cardiac arrest.