Answer:
A). Activation of SYMPATHETIC nervous system by new experience.
Step-by-step explanation:
According to the studies, the initial increase in heart and the breathing rates at the time of skin diving trip was mainly an outcome of the 'activation of sympathetic nervous system due to the new experience'. The new experience causes a 'fight or flight response' that secretes 'adrenaline' and thus, it eventually end up in 'elevated pulse rates' and 'breathing' during the trip that indicates the activation of 'sympathetic nervous system'. Thus, option A is the correct answer.