Final answer:
In Python, variable names can start with an underscore (option a), but they cannot start with a number (option b).
Python variable names can start with an underscore (option a), and the data type of variable names does not need to be declared (option d). Therefore, the correct answer is option b.
Step-by-step explanation:
The incorrect statement regarding variables in Python is:
b. Variable names in Python cannot start with a number. However, it can contain a number in any other position of the variable name.
Python variable names can start with an underscore (option a), and the data type of variable names does not need to be declared (option d). Therefore, the correct answer is option b.
The incorrect statement regarding variables in Python is that the data type of variable names should not be declared. Python uses dynamic typing, meaning that variables do not require an explicit declaration to reserve memory space.
The incorrect statement regarding variables in Python is d.Data type of variable names should not be declared. In Python, the data type of a variable is not explicitly declared; it is determined at runtime based on the value assigned to the variable. Therefore, statement 'd' is incorrect because it implies a requirement for declaring a variable's data type, which is not the case in Python.
Regarding the other options: a) Variable names can indeed start with an underscore, and b) Variable names cannot start with a number but can contain numbers in other positions.