I've looked this question up. The part that is supposed to be underlined is storm surge.
Answer:
The word underlined in the sentence above is best defined as C. a large wall of water that is forced onto shore by storm winds.
Step-by-step explanation:
A storm surge is a term that refers to the rising of water level in the ocean. This rise goes above the level of a predicted tide and is caused solely by a storm. Having that in mind, we can see that, among the options given, the one whose definition best fits the explanation above is C. a large wall of water that is forced onto shore by storm winds. Even if we did not know the definition for storm surge, we could guess by paying attention to context clues. In the sentence, it is said that the storm surge causes flooding. We can eliminate options A and B, since they have no connection with floods. As for letter D, it is the definition of a hurricane, so it does not apply to a storm surge.