You are product manager for Brand X diapers, a national brand. Brand X has been declining in absolute level of sales for the last four consecutive months. You ask the marketing research department to do a study to determine why sales have declined. The most appropriate research type would be _________.
A. A laboratory experiment
B. A field experiment
C. A descriptive study
D. An exploratory study
E. A causal study of actual and potential customers
Answer: D. An exploratory study