The Major Difficulty with the Case Study Method as a Basis

Multiple Choice

The major difficulty with the case study method as a basis for drawing cause-and-effect conclusions is that

A) coding of the results cannot be done reliably and validly.
B) the simultaneous use of several treatments and failure to control extraneous variables prevent causal inference.
C) excessive constraints on the external validity of the case study prevent causal inference.
D) biases of the researcher must dominate the interpretation of the results.