abbreviations with periods within quotes

[Grammarholic]

Are these 3 correct with American punctuation?

When you use the word "etc.," make sure the word is used accurately.

When you use the word "p.m.," make sure to include the periods between the letters.

If you use the word "et al.," please explain what it means.

Are these 3 correct with American punctuation?

When you use the word 'etc.', make sure the word is used accurately.

When you use the word 'p.m.', make sure to include the periods between the letters.

If you use the word 'et al.', please explain what it means.

Thanks, and which looks better above-- the American or British version?

[Mister Micawber]

These are correct:

When you use the word 'etc.', make sure the word is used accurately.
When you use the word 'p.m.', make sure to include the periods between the letters.
If you use the word 'et al.', please explain what it means.
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Native English teacher at Mister Micawber's