Select all possible TRUE statements.

Question $6$ options:

The main difference between an array an a matrix is that matrices are restricted to two dimensions while arrays can have an arbitrary number.

A matrix is similar to a data.frame in that it is rectangular with rows and columns except that every single element, regardless of column, must be the same type.

Both dataframes and matrices are data structures of equal$-$length vectors.

A List can store any number of items of any type.