The correct options are
A To help them lead better lives.
B To help them act responsibly.
C To prevent discrimination on any lines.
D To ensure every citizen is equal before the law.
The Indian constitution lays down certain rights and duties for the citizens of India to help them lead better lives. Fundamental duties tell citizens to act in a responsible manner. Fundamental rights prevent discrimination because it does not differentiate on the lines of caste, creed, sex, language or religion. This ensures that every citizen is equal before the law.