As per the Constitution of India, which of the following statement(s) is/are correct ?
(a) The state may make provision for securing just and humane conditions of work.
(b) The state shall endeavour to provide early childhood care and education for all the children until they complete the age of six years.
(c) The state shall not endeavour to secure for the citizens a uniform civil code in the territory of India.
(d) The state shall endeavour to protect and improve the environment and to safeguard the forests and wildlife of the country.
Select the correct answer from the codes given below :

Read Assertion (A) and Reason (R) and answer using the codes given below :
Assertion (A) : No minimum age is prescribed for appointment as a Judge of the Supreme Court of India nor is there any fixed period of office.
Reason (R) : The original jurisdiction of the Supreme Court is dealt within Article-132 of the Constitution of India.

In which one of the following cases the Supreme Court of India had invalidated a Constitutional Amendment for non-compliance with the procedure contained in the proviso to clause (2) of Article-368 ?