The function  p(d)=5⋅4d−1 represents the number of people who receive a certain e-mail on day d of an e-mail experiment. What does the value 5 represent in this situation?  There are 5 people running the experiment.Every day, the number of people receiving the e-mail increases by 5%.Every day, the number of people receiving the e-mail increases by 5.Five people received the e-mail on the first day of the experiment.