Robert Springer Woke Up in the Morning and Felt a Sense

Robert Springer woke up in the morning and felt a sense of joy and peace as he got ready for work. At work, though challenges came his way, he tackled them without getting stressed about them. This feeling lasted for several days that week. What is one of the reasons that Springer's feeling can be categorized as a mood and not as an emotion?

A) It is indicated by a facial expression.
B) It is brought about by a specific event.
C) It is prolonged in nature.
D) It is a positive feeling.
E) It is more intense than emotions.