Final answer:
Initial unexpected panic attacks usually occur without a specific trigger, happening unpredictably and even during times of relaxation or sleep.
Step-by-step explanation:
Most initial unexpected panic attacks typically occur without a specific trigger (D).
Panic attacks can happen unpredictably in any situation, and many people report that their first panic attack felt like it came 'out of the blue.'
While stress can be a contributing factor, these attacks can occur even when a person is relaxed or asleep.
It's also possible for panic attacks to be linked to certain places or situations, such as crowded places, likely due to a previous panic attack occurring in a similar setting, creating a form of conditioned response.
Nonetheless, the first unexpected panic attack often lacks an identifiable cause at the moment it happens.
correct option D) Without a specific trigger