Correct Option :
D) The statement that Dadra and Nagar Haveli were under French colonial rule till 1954 is incorrect. Dadra and Nagar Haveli were under Portuguese colonial rule until 1954. They were liberated from Portuguese rule in 1954 and subsequently integrated into the Indian Union.
Incorrect Options:
A) Goa attained full statehood in 1987. This is correct. Goa was granted statehood on May 30, 1987, becoming the 25th state of the Indian Union through the Goa, Daman and Diu Reorganisation Act, 1987.
B) Diu is an island in the Gulf of Khambhat. This is correct. Diu is an island located off the southern coast of Gujarat, at the mouth of the Gulf of Khambhat (formerly Gulf of Cambay).
C) Daman and Diu were separated from Goa by the 56th Amendment of the Constitution of India. This is correct. The 56th Amendment Act, 1987, facilitated the creation of the state of Goa while retaining Daman and Diu as a separate Union Territory. Prior to this, Goa, Daman, and Diu constituted a single Union Territory.