Drug addicts are enrolled in two different residential treatment programs that differ in length $($treat $=0$ is short, treat $=1$ is long$).$ The patients are assigned to two different sites $($site $=0$ is site A$,$ site $=1$ is site B$).$

Herco indicates heroine and cocaine use in the past three months $(1=$ heroine and cocaine use, $2=$ heroine or cocaine use, $3=$ neither heroine or cocaine use$).$ Other variables recoded were age at time of enrollment, ndrugtx $($number of previous drug treatments$),$ time until return to drug use, and censor $(1=$ return to drug use, $0=$ censored$).$

With each year increase in age of enrollment, the risk of relapsing:

Group of answer choices

Decreases by $1\mathrm{.}3\%(1\mathrm{.}00-0\mathrm{.}987).$

Increases by $1\mathrm{.}3\%(1\mathrm{.}00-0\mathrm{.}987).$

Multiplies by $3\%(0\mathrm{.}3*0\mathrm{.}987).$

Remains the same.