Final answer:
Character is not a separate data type in Python, as single characters are considered strings; therefore, 'Character' is the invalid data type among the options.
Step-by-step explanation:
The student has asked which of the following is not a valid data type in Python:
- Integer
- String
- Boolean
- Character
In Python, the valid data types are integer, string, and boolean. However, character is not a separate data type in Python, as single characters are simply strings of length one.
Therefore, the correct answer is Character.