which statement from fdr's speeches uses parallel structure?

a. no matter how long it may take us to overcome this premeditated invasion, the american people in their righteous might will win through to absolute victory.
b. admittedly the damage is serious. but no one can say how serious.
c. american ships have been sunk; american airplanes have been destroyed.
d. i do not think any american has any doubt of our ability to administer proper punishment to the perpetrators of these crimes.

The correct answer is C) "American ships have been sunk; American airplanes have been destroyed."

Parallelism is a figure of speech in which sentences or phrases hace the same grammar structure.

Parallelism is achieved when the same grammar pattern is follow in sentences.

In this example, both are simple sentences with a the same subject pattern (American ships-American airplanes) and also with the same verb tense pattern (present perfect "have been sunk-have been destroyed.)

c, his tragic flaw to cause his downfall