Feed-forward control anticipates problems before they occur

You want to observe how often consumers listen to music throughout their day and what different audio devices they use. You are also interested in how consumers store and access their own music collections. You should conduct ________ research

A) causal B) experimental C) secondary D) pure E) exploratory

Which of the following is true?

A. The delta of a European put equals minus the delta of a European call B. The delta of a European put equals the delta of a European call C. The gamma of a European put equals minus the gamma of a European call D. The gamma of a European put equals the gamma of a European call