The correct answer is option 4 - None of the (a), (b) and (c) above. Overload of Zamindars.

Option 1 suggests that the reason for increased litigation was due to the strengthening of Zamindars` position against the ryot (tenants). However, while it`s true that the land settlement system put the Zamindars in a powerful position, it doesn`t explain why litigation increased.

Option 2 proposes that the East India Company becoming the overload of Zamindars led to more litigation. While the company did have increased control over the Zamindars, it`s not a plausible reason for a rise in lawsuits.

Option 3 suggests that more efficient judicial systems resulted in more litigation. However, the land settlement system introduced by Lord Cornwallis didn`t necessarily make the judicial system more efficient.

Therefore, none of the options (a), (b) and (c) provide a satisfactory explanation for the increase in litigation post the introduction of the land settlement system of Lord Cornwallis. In actuality, this increase is often attributed to the legal requirement introduced by Lord Cornwallis that made disputes about land ownership matters for a court of law to decide.