Based on the results presented what role does the mutation play does the P1K13CA gene type (mutant or wild) with regards to the relationship between morality and aspirin usage? (Confounded, effect modifier, neither)A) the overall relationship between mortality and aspirin usage is confounded by P1K13CA gene type differences between the aspirin and no aspirin groups.B) the overall relationship between mortality and aspirin usage is modified by the P1K13CA gene type C) since the P1K13CA gene type is not associated with mortality it can neither confound nor modify this associationD) since this is an observational study, P1K13CA gene type can confound but cannot modify the association between mortality and aspirin usage.

"We obtained data on 964 patients with rectal or colon cancer from the N the Health Professionals Follow-up Study, including data on aspirin use after diagnosis and the presence or absence of PIK3CA mutation" -observational shely "We used data from two prospective cohort studies , the Nurses' Health Study (NHS, involving 121,700 women who were enrolled in 1976) and the Health Professionals Follow-up Study (HPFS, involving 51,500 men who were enrolled in 1986)." Additionally, when discussing the aspirin exposure assessment: "Assessment of aspirin use in the NHS and HPFS cohorts has been described in detail previously. In 1980, NHS participants were asked whether they regularly used aspirin in most weeks, as well as the dose and duration of use; thereafter, this information was updated biennially (except in 1986). Beginning in 1986, HPFS participants were asked whether they regularly used aspirin two or more times each week; after 1992, information on the average dose used each week was requested." The authors present the following graphic as part of the article. The starting point (time 0) forw each patient in the same was year of diagnosis. A Colorectal Cancer-Specific Mortality, Mutant PIK3CA B Colorectal Cancer-Specific Mortality, Wild-Type PIK3CA gown memess 05- 04- 04 03- No aspirin use see Probability of Death Probability of Death Aspirin use P