Is blocking, confounding and replication present in this study? I'm sure 2 of my answers are correct, so I'm suspecting it's the 2nd question.

{3 points) A researcher is interested in studying the effect of iron on human memory so he comes up with the following plan for an expen'ment. The experiment will involve 100 volunteers where 50 volunteers are randomly selected from all female volunteers and 50 are randomly selected from all male volunteers. Each volunteer will take a memory test 30 minutes after eating spinach. Some volunteers will be randomly assigned to eat ironfree spinach; some will eat regular spinach (with iron); others Wlll eat a mixture of the two which contains only half the amount of iron. For each volunteer, a test score (the number of items recalled oomectly) will be recorded. The volunteers will not be told which type of spinach they have been given, but the researcher who evaluates the results will prepare the cans of spinach right on the spot (out of sight of the volunteers). Part i) What sampling technique is used to obtain the 100 volunteers to participate in the study? C.) A. Stratied random sampling C) B. Twostage cluster sampling 0 C. Simple random sampling C) D. Systematic sampling C) E. Onestage cluster sampling Part ii) Which of the following features isfare present in this study? CHECK ALL THAT APPLY. A. Single blinding :] B. Confounding :] C. Blocking 3 D. Double blinding :] E. Replication :] F. None of the above Part iii} The treatments of this study isfare: Q A. a can of spinach 0 B. iron 0 C. ironfree spinach and regular spinach with iron :0) D. no iron, half dose of iron and full dose of iron