If a broker/dealer decides to store records electronically, which of the following criteria must be met?

i. the records must be stored in a manner which allows the broker/dealer to produce them upon request in a prompt manner.
ii. publication of such electronic records must take place at least on an annual basis.
iii. duplicate copies of the records must be maintained at two separate locations.
iv. records must be stored in a format which does not allow the modification of files.

The authors of the paper "fudging the numbers: distributing chocolate influences student evaluations of an undergraduate course"† carried out a study to see if events unrelated to an undergraduate course could affect student evaluations. students enrolled in statistics courses taught by the same instructor participated in the study. all students attended the same lectures and one of six discussion sections that met once a week. at the end of the course, the researchers chose three of the discussion sections to be the "chocolate group." students in these three sections were offered chocolate prior to having them fill out course evaluations. students in the other three sections were not offered chocolate. the researchers concluded that "overall, students offered chocolate gave more positive evaluations than students not offered chocolate." indicate whether the study is an observational study or an experiment. give a brief explanation for your choice.