Question

which type of muscle is the hardest to get tired or fatigued?
skeletal
smooth
cardiac

Explanation:

Cardiac muscle (the third partially obscured option) is the muscle type that resists fatigue the most. It has a high density of mitochondria and a constant oxygen supply via coronary vessels, allowing it to contract continuously without tiring, unlike skeletal (fatigues with exertion) and smooth (fatigues slower than skeletal but faster than cardiac) muscle.

Answer:

Cardiac (the third partially visible option)