is or are?

[Cw1234]

Can anyone tell me whether the "be" verb in this sentence should be "is or are". I found this in a newsletter from this site. Thank you.

Which of these two greetings is more appropriate?

[Daemon99]

'is' sounds correct to me. There are two greetings and one of them is appropriate and you are asking which one it is.

This is how I figure it.

If the answer to a question is singular, like, 'Who is the tallest of them all?', then you go for is. But if it is plural, like, 'Who are the tall guys among them?', then you go for are
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Non-native speaker of English
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I intend to live forever - so far, so good.