Given the following context:  Naomi Bishop is a senior investment banker who deals with IPOs. After her latest project is undervalued she faces professional setbacks including clients losing confidence in her work. To bounce back she is hired to handle the IPO for Cachet, a privacy company with a social networking platform.  Around the same time Naomi bumps into Samantha Ryan, an old college classmate who now works as a public attorney. Unbeknownst to Naomi, Samantha is investigating Naomi's on-again, off-again boyfriend Michael Connor, a broker at the same firm as Naomi who Samantha suspects is involved in insider trading. Michael tries to get information from Naomi about Cachet but fails.  While doing due diligence, Naomi learns from Marin, one of the coders, that Cachet is hackable. Despite having a nagging feeling that something is wrong, the numbers check out and Naomi continues to try to sell the shares of the company to investors. Michael, who has had no new insider trading tips to pass on to his friends at investment firm Titanite, tries unsuccessfully to hack into Naomi's phone. Vice President Erin Manning, Naomi's assistant on the IPO, learns that Marin has been fired. To warn Naomi of this, she goes to Michael's home after not being able to reach Naomi and ends up leaking the information to him in the hope that he will be able to get her a promotion, something Naomi has been unable to do for her. Michael leaks the tips to his friends at Titanite and then sends the story to an old college roommate who is a tech journalist. Naomi figures out that it was Erin who betrayed her, based on her having a green pen, the same type of pen that Michael uses. When the shares open, confidence is lost and the company loses a third of its value on the first day of trading.  answer the following question:  What is the last name of the person who betrayed Naomi?
A:
Manning