Heidi decided to make extra money by offering to do investments for her friends for a fee. She actually did no investing, but used the funds from new friends to pay off earlier enrollees. This worked well for a while, but her scheme came to light when her supply of new friends came to an end. She is guilty of which of the following practices?
a. Operating a Ponzi scheme
b. Operating a bait and switch scheme
c. Account kiting
d. Pretexting
e. Defalcation