Which of the following is an effective way to gain a client referral?

a$)$ Ask when you speak with them for the first time

b$)$ Have the prospect bring a friend to their success session with them

c$)$ Have the client call three friends at the point of sale

d$)$ Ask the client for three of their friend's names at their first training session

e$)$ Require the client to give you the names of $2$ friends to sign up