The correct answer is indeed option 2: II only. Let`s delve into why each option stands.

Option 1 suggests that the Ikshvaku rulers of Southern India were against Buddhism. However, this is not accurate as historical evidences show that they were actually supporters of Buddhism. Hence, statement I is incorrect.

Option 2 states that the Pala rulers of Eastern India were patrons of Buddhism. This is accurate, as the Pala dynasty was known for its patronage towards Buddhism, and they strongly supported Buddhist institutions and teachings. Therefore, statement II is true.

Option 3 suggests that both statements I and II are correct, which is inaccurate as statement I is false.

Option 4 implies that neither of the statements are true and it is incorrect as statement II is true.

Accordingly, the answer is option 2, which affirms that the Pala rulers supported Buddhism.