Given three different dataset descriptions, create the appropriate R structure (list or data frame) for each one.

• For the survey responses, use a structure that can handle fields of different types and allow for missing fields.
• For the student grades, use a structure that is well-suited for tabular, row-and-column data where all rows share the same variables.
• For the mixed-type records, use a structure that can hold a numeric vector, a character, and a logical value together.