Which words in the following sentence should be capitalized? when the queen herself threw the switch on the world's first atomic power plant at calder hall outside london in 1956, nuclear reactors were seen as a source of cheap, pollution-free energy.

A) When, Calder Hall, London

B) When, Queen, Calder Hall, London

C) When, Calder Hall, London, Nuclear Reactors

D) When, Queen, Atomic Power Plant, London

The correct answer would be B, When, Queen, Calder Hall and London.

Explanation:

We always capitalize words when a paragraph or sentence is starting, when an important name is used, when a place is being written, or simply when a noun is used, etc. So in this sentence, Sentence is starting from 'when', so It will be written in Capital Letters. Secondly, queen is considered to be an important person, so it will also be written in capital letter. Next, the name of the town is mentioned, i-e calder hall, which will also be written in capital letters. In the last, city name is being used, 'london', which will also be written in capital letters. So option B is the most appropriate one.

A - the queen isn't specified which one so its to capitalized same with nuclear reactors and atomic power plant (aka they aren't proper nouns)