Jeff, an employee at Citrus Inc., hears about a change in the company's leave policy from one of his coworkers and shares this information with another coworker, Judy. Judy, in turn, passes on the information to her teammates. However, this information has not been officially confirmed. In this scenario, the information is exchanged through _____.
a. external communication
b. upward communication
c. formal communication
d. grapevine communication