Answer:
a. was in a positive emotional state in anticipation of a reward.
Explanation:
Positive emotion: The term "positive emotion" is being considered as an individual's feeling where he or she lacks negativity so that he or she doesn't feel any discomfort or pain. However, Frederickson during 2009 stated ten common and different positive emotions including love, joy, pride, serenity, gratitude, amusement, interest, awe, hope, and inspiration.
In the question above, the given context represents that Jack was experiencing positive emotions as he was going to meet his girlfriend which is considered as a reward in this scenario.