Researchers Are Looking at the Link Between Colorectal Cancer and the Usage

Researchers are looking at the link between colorectal cancer and the usage of nonsteroidal anti-inflammatory drugs. They interviewed a group of patients with biopsy-proven colorectal cancer, followed by a group of patients' neighbors of comparable age and race. The study is based on comparing the outcomes of two individuals with similar features (one from each of the two groups) . Which of the following possible issues with this study is best addressed by this design technique?

A) Ascertainment bias
B) Confounding
C) Observer bias
D) Recall bias
E) Selection bias