Concept:An unwritten constitution relies mainly on customs, conventions, and established practices rather than a single codified document.
Explanation:A country with an unwritten constitution does not keep all its fundamental rules in one written legal document.
Instead, its system of government is shaped by parliamentary laws, judicial decisions, customs, and conventions.
These customary laws and conventions are accepted as binding and guide how political institutions operate.
They are a vital and defining feature of an unwritten constitution, even though they may not be formally written down.
Answer:C. contains customary laws and conventions