"Provisions relating to fundamental duties cannot be enforced by writs. They can be only promoted by constitutional methods. But they can be used for interpreting ambiguous statutes." In which one of the following cases was the aforesaid principle enunciated?

A. Moti Lal v. State of Uttar Pradesh

B. Civil Rights Committee v. Union of India

C. Head Masters v. Union of India

D. Magan Bhai v. Union of India

Answer: Option C