Which of the following statements is false regarding issues around the Synchronoss Technologies, Inc. restatement?

a. The issue at the heart of the restatement was that the company recorded revenue for contracts containing side letter agreements. 

b. A side letter is an agreement that is supplementary to a primary contract and might include providing price discounts contingent on the customer making larger than normal purchases or purchases immediately prior to period-end. 

c. The structure of executive compensation was based almost completely on using fixed salaries rather than bonuses based on stock performance or company profitability. 

d. All of the above (a–c) are false.