Take context from the input text and decide on the accurate relationship between 'Thomson Reuters' and 'software' from the options provided.
Options: stock exchange, chairperson, employer, product/material produced

Symantec Corp, the antivirus and security software maker best known for its Norton antivirus software, is expected to report first-quarter earnings slightly below analysts' expectations on Tuesday, according to Thomson Reuters I/B/E/S.
product/material produced