One Argument for NOT Conducting Statistical Tests for Single-Case Experiments

One argument for NOT conducting statistical tests for single-case experiments is that

A) there are no statistical tests than can be conducted with a sample size of one.
B) statistical significance is not the same thing as clinical significance.
C) treatment effects are usually small; it would be difficult to achieve statistical significance in a single-case experiment.
D) in order to conduct statistical tests, researchers would need to collect more data than is feasible for most single-case experiments.