Article: Beyoncé has worked with Pepsi since 2002, and in 2004 appeared in a Gladiator-themed commercial with Britney Spears, Pink, and Enrique Iglesias. In 2012, Beyoncé signed a $50 million deal to endorse Pepsi. The Center for Science in the Public Interest (CSPINET) wrote Beyoncé an open letter asking her to reconsider the deal because of the unhealthiness of the product and to donate the proceeds to a medical organisation. Nevertheless, NetBase found that Beyoncé's campaign was the most talked about endorsement in April 2013, with a 70 per cent positive audience response to the commercial and print ads.

Question: Which organization wrote a letter to Beyonce after her Pepsi endorsement deal?
The Center for Science in the Public Interest (CSPINET)