Why does the author include these sentences in the article?

Yes, the correct and best option is:

to show that militaries from all over the world have used bicycles...

C) To show that militaries from all over the world have used bicyclesB

This is the correct answer because the sentences address armies from different regions of the world (Japan, Great Britain, Sweden)

Choice A is incorrect because no improvements are demonstrated in the sentences.

Choice B is incorrect because peacetime is not mentioned in any of the sentences.

Choice D is incorrect because the sentences do not discuss different uses of bicycles.

Hope this helps!!

c is the answer because first she would blush to make the reader wonder why which they find out in the next line.