To answer this question, we need to understand the concept of arrays and datatypes in programming.

An array is a data structure that can hold a fixed number of elements of the same datatype. Each element in the array is accessed by its index.

Now let's go through each option and determine if an array can hold that datatype:

A. TextBoxes: This option refers to a graphical user interface element used for user input. In programming, TextBoxes are usually represented by objects or classes. Therefore, an array can hold TextBox objects.

B. Labels: Similar to TextBoxes, Labels are another graphical user interface element used for displaying text. Labels are also represented by objects or classes, so an array can hold Label objects.

C. Structures: A structure is a user-defined data type that can hold different types of data under a single name. An array can hold structures, as long as all the elements in the array have the same structure type.

D. Controls: Controls refer to various graphical user interface elements, such as TextBoxes, Labels, Buttons, etc. Since we have already established that arrays can hold TextBoxes and Labels (which are types of controls), an array can hold Controls.

E. An array can hold all of the above: This option is correct. Arrays can hold TextBoxes, Labels, Structures, Controls, and any other data type as long as all the elements in the array have the same datatype.

Therefore, the correct answer is E. An array can hold all of the above.