Step 1: Understanding the concept.
The doctrine of Irretrievable Breakdown of Marriage allows divorce when a marriage has completely failed and there is no possibility of reconciliation.
Step 2: Law Commission’s role.
The 205th Report of the Law Commission of India (2008) recommended that this should be recognized as a valid ground for divorce under the Hindu Marriage Act, 1955.
Step 3: Elimination of options.
(b), (c), and (d) correspond to other topics covered by the Law Commission and are unrelated to this recommendation.
\[
\boxed{(a)}
\]