52.
The answer is: C
Explanation
The correct option is C: Both (a) & (b).
This is because the doctrine of res judicata is based on three maxims, two of which are given in options (a) and (b). The maxims are:
Nemo debet bis vexari pro una et eadem causa: It means no man shall be vexed twice for the same cause. This maxim reflects the principle of finality of judgments and prevents multiplicity of suits on the same matter between the same parties.
Interest reipublicae ut sit finis litium: It means it is in the interest of the state that there should be an end to litigation. This maxim reflects the principle of public policy and ensures that litigation does not drag on indefinitely and consume the resources of the state and the parties.
Res judicata pro veritate accipitur : It means a judicial decision must be accepted as correct. This maxim reflects the principle of conclusiveness of judgments and implies that a court's decision on a matter is final and binding on the parties and cannot be challenged or reopened in a subsequent suit.
Therefore, option C is correct as it includes both (a) and (b), which are two of the three maxims on which the doctrine of res judicata is based. Option A is incorrect as it only includes one maxim. Option B is incorrect as it only includes one maxim. Option D is incorrect as it implies that either (a) or (b) is sufficient, which is not true.