A Researcher Is Interested in the Effects of a Vegetarian

Multiple Choice

A researcher is interested in the effects of a vegetarian diet on memory. One group eats a strict vegetarian diet for three months, a second group eats a strict vegan diet for three months, while a third group eats anything they want for three months. After three months, all participants are given a memory test. Results indicated that memory was is better for both the vegetarian and vegan groups. In this study, the independent variable is

A) the three month time frame
B) scores on the memory test
C) the type of diet
D) the vegetarian diet but not the vegan diet
E) impossible to tell in this situation