X-rays . were invented by the British Army
reduced infection after surgery
were discovered by accident
have no uses today

b

Explanation:

The correct answer is A. was discovered by accident

Explanation:

X-rays are a type of radiation mainly used for medical uses as this radiation allows doctors to create images of inner structures that are helpful for diagnosis, also, X-rays are used as part of radiotherapy to treat cancer. Additionally, X-rays were discovered in 1895 by Wilhelm Rontgen who discovered them by accident as he studied electrical discharge tubes and noticed there was an unknown or "x" type of radiation, based on this, he described X-rays and even use them to create an image of his hand. Thus, the answer is X-rays were discovered by accident.

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answer; the correct answer is (operating system);