Assertion (A): Courts, through its judicial review practice, have liberalized the doctrine of locus standi for the enforcement of fundamental rights of those who lack access to courts due to the reasons of poverty or social and economic disabilities.
Reasoning (R): Public or Social Action Litigation (PIL or SAL) means any public spirited person can petition or write letters to courts on behalf of the human rights violation victims or aggrieved parties.

Both A and R are correct and R is the correct explanation of A.

Option 1: Both A and R are correct, and R is the correct explanation of A.

Explanation:
Assertion (A) states that courts have liberalized the doctrine of locus standi for the enforcement of fundamental rights for individuals who lack access to courts due to poverty or social and economic disabilities. This assertion is correct, as many legal systems, especially those concerned with human rights, have expanded the scope of locus standi to facilitate access to justice for marginalized groups.
Reasoning (R) explains one mechanism through which this is achieved, namely Public or Social Action Litigation (PIL or SAL), where public-spirited individuals can petition or write letters to courts on behalf of human rights violation victims or aggrieved parties. This also accurately describes the concept of PIL or SAL, which helps in widening the access to justice for those who cannot approach courts themselves due to various reasons.

PIL is a direct consequence of the courts liberalizing the doctrine of locus standi in judicial review. By allowing PIL, courts are ensuring that even those without the means to fight for themselves can have their fundamental rights protected.

So, both A and R are true, and R explains how judicial review practices like PIL achieve the goal mentioned in Assertion (A).