The correct options are
A If the executive fails to perform its duties, members of the legislature can question them.
B The President can send back the laws passed by the legislature, if it is found to be unconstitutional.
C If the legislature passes unjust laws, the courts can strike them down.
The legislature, judiciary, and the executive are allowed to perform their functions and also check the excess of other organs of the government. This is known as the system of checks and balances. The term ‘horizontal distribution of powers’, is used to denote the three organs of government that have been given comparable powers.