The correct answer is C. 30 years.
The Constitution of India, Article 173, states that a person shall not be qualified to be a member of the Legislative Council unless he is a citizen of India and has completed the age of thirty years.
The other options are incorrect. Option A is the minimum age required to be a member of the Lok Sabha. Option B is the minimum age required to be a member of the Rajya Sabha. Option D is the minimum age required to be a member of the State Legislative Assembly.