Answer:
A). Trepidation.
Step-by-step explanation:
As per the question, the word that best completes and accomplishes the meaning of the given sentence would be 'trepidation'. The word 'trepidation' implies 'a hesitant, concerned, or fearful state or condition' which the humans naturally feel before approaching any kind of new journey, experience, etc. Thus, the sentence gives the meaning that 'it is quite instinctive for humans to approach any new experience with trepidation(a hesitance or fear)'. Therefore, option A is the correct answer.