Exp) Option a is the correct answer.

Statement a is correct: The most widely accepted definition of citizenship is ‘full and equal membership of a political community’. Citizenship is the status of a person recognized under the custom or law as being a legal member of a sovereign state or belonging to a nation.

Statement b is incorrect: Citizenship indicates the relationship between an individual and a nation state. Normally, the individual is conferred protection by the state, in return for the fulfilment of certain obligations owed by the individual to the state.

Statement c is incorrect: The relation of citizenship has never been fixed or static, but constantly changes within each society. As a bond, citizenship extends beyond basic kinship and is a tool to unite. It usually signifies membership of a political body. Often heterogeneous society form a common national identity. E.g. India, USA.

Statement d is incorrect: Citizenship is equality of status as well as rights.