A study is done to gather evidence on whether smoking (or equivalent) affects students' grade point average at a certain university. The researchers gather information on a random sample of the students at the university. They obtain the grade point averages of the students and information about whether they use nicotine-based products (smoking or e-cigarettes.) Assume there is a good response rate and that the information available about their habits and the GPAs is accurate. From the design of the study, determine which one of these is the best summary of the types of conclusions that may be made. a. Cannot generalize to the population and cannot provide evidence for causality b. Cannot generalize to the population but can provide evidence for causality. c. Can generalize to the population but cannot provide evidence for causality. d. Can generalize to the population and can provide evidence for causality