This is an ellipsis question and the golden rule that always works for ellipsis is that the words that are assumed must have already appeared in the sentence before. In other words, you cant assume words that have not already appeared in the sentence.
If A was true, the sentence would be:
The intrusion of politics into the modern Olympics has created, as it will no doubt continue to (create) frustration for athletes and fans who would prefer to see the games represent only competition among the excellent from all nations.
So, create is assumed, but notice that create has not appeared already appeared in the sentence before.
If B was true, the sentence would be:
The intrusion of politics into the modern Olympics has created frustration, as it will no doubt continue to (create frustration), for athletes and fans who would prefer to see the games represent only competition among the excellent from all nations.
So, create frustration is assumed, but notice that create has not appeared already appeared in the sentence before.
If D was true, the sentence would be:
The intrusion of politics into the modern Olympics has (created frustration) and will no doubt continue to create frustration for athletes and fans who would prefer to see the games represent only competition among the excellent from all nations.
So, created frustration is assumed, but notice that created has not appeared already appeared in the sentence before.
If E was true, the sentence would be:
The intrusion of politics into the modern Olympics has created frustration, and will no doubt continue (to create frustration), for athletes and fans who would prefer to see the games represent only competition among the excellent from all nations.
So, to create frustration is assumed, but notice that create has not appeared already appeared in the sentence before.
Hence, C is the correct answer.