Which Text Box entry would result in an error message based on the expression in the Error Message tool's configuration?

The expression provided in the choice that results in an error message is based on how the syntax and the parameters of the Contains function are structured in Alteryx.

The correct answer includes the '!' operator, which denotes a logical NOT. This operator should be used properly with a valid Boolean expression. In this case, the syntax uses the Contains function with the field reference [#1] but lacks a valid construction for evaluating the presence of the substring.

The Contains function works by taking a string and checking if it contains a specified substring. When negated using the '!' operator, it still needs to produce a Boolean outcome for the system to evaluate correctly. Since the expression isn't structured to properly leverage the Contains function with appropriate arguments, it leads to an error.

In contrast, the other choices consist of valid uses of the Contains function. They check if specific strings are present within the given field or string, aligning correctly with the requirements of the function's syntax. Hence, those expressions do not produce errors.