Answer:
B) with an explanation of the event
Explanation:
The key event in this paragraph is illustrated with its explanation.
The first sentence introduces the mentioned key event - the invasion of Normandy. This sentence is called the topic sentence, and it tells us what the rest of the paragraph will be about.
The rest of the sentences are supporting sentences - sentences that contain information that clarifies, explains, describes, or illustrates the idea introduced in the topic sentence. Here, they explain to us what happened during the invasion of Normandy and why this event is so important.
