Step 1: Definition of Kāraṇatāvāda.
Kāraṇatāvāda, meaning the principle of causation. In Buddhist philosophy, it is explained that the existence of all phenomena is dependent on other causes and is not independent.
Step 2: Pratītya-samutpāda.
According to this principle—"Idam pratyayāt idam utpadyate" (when this exists, that arises).
This is the principle of dependent causation, clarified by the twelve links of dependent origination (dvādaśa-nidāna).
Step 3: Analysis of Options.
(1) Āryāṣṭāṅgika mārga: This is the path to liberation, not a principle of causation.
(2) Pratītya-samutpāda: Absolutely correct; this is known as kāraṇatāvāda.
(3) Anityatā: This is the principle of impermanence, but not equivalent to the principle of causation.
(4) Dukhanirmūlana: This is the objective, not the principle.
Step 4: Conclusion.
The correct answer to this question is—Pratītya-samutpāda.