The correct answer is: C. Either I or II is implicit.
The statement is about the mightiest superpower not always winning wars and getting accolades from other countries. This does not mean that winners are never admired or appreciated, or that they are never criticized. It simply means that there is no guarantee that a superpower will always win wars and get accolades, even if it is the mightiest.
Assumption I states that winners are sometimes admired and appreciated. This assumption is consistent with the statement, because it does not contradict the statement. The statement does not say that winners are never admired or appreciated, so assumption I is possible.
Assumption II states that winners are occasionally criticized. This assumption is also consistent with the statement, because it does not contradict the statement. The statement does not say that winners are never criticized, so assumption II is also possible.
Therefore, either assumption I or assumption II is implicit in the statement.