Step 1: Understanding the Concept
A polar molecule has a permanent dipole moment because the centres of positive and negative charge do not coincide.
Step 2: Detailed Explanation
(A) True: polar molecules have a permanent dipole moment.
(B) True: this is the definition.
(D) True: they behave like tiny electric dipoles.
(C) A symmetrical shape tends to make the charge centres coincide, giving zero dipole moment. So a polar molecule cannot be described as symmetrical, and (C) is the wrong statement.
Final Answer:
Statement (C) is the wrong one, option (C).
\[ \boxed{\text{(C)}} \]