<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A researcher has identified a chemical compound that she expects may contribute to the development of colorectal cancer. She designs an experiment where she exposes 70 mice to a diet containing this compound with another 50 mice in a control group that was fed a regular diet. After 9 months, the mice were evaluated for tumor development at necropsy. In total, 14 mice in the experimental group developed colorectal tumor burden, and 1 mouse in the control group developed tumors. Based on this experiment, what risk of colorectal cancer can be attributable to this chemical compound?? A: 2.0, B: 12.5, C: 18.0, D: 20.0, E: 22.0,  <response>: This is a question about calculating attributable risk from an experimental study comparing mice exposed to a chemical compound to unexposed control mice. To calculate attributable risk, we need to know the incidence of disease in the exposed group versus the unexposed group. Here, 1470 20 of exposed mice developed tumors, compared to 150 2 of unexposed mice. The attributable risk is the difference in incidence between these groups, which is 20 - 2 18. C: 18.0 