Pluralising abbreviations question

[Moln]

How do you do it?

For example in a document 'active period' is shortened to a/p. Further along the document several active periods are referred to, should it be:

a/ps, or
a/p's

A/ps is ugly, but a/p's is plain wrong.

Prefer a/ps to a/p's (as both words are shortened it makes no sense to have an apostrophe on the second) but far better would be A/Ps. Somehow clearer to have the abbreviation in upper case, although if that's not normally how it's done in this case you have to use the generally used version.

I'd go with A/P and A/Ps

I'd change to AP and APs. You don't need an oblique. Define it at first occurrence: 'active period (AP)' then just use 'AP' after.

Definitely AP and APs.

Agree that a/ps looks ugly but a/p's is wrong.

I'd prefer no oblique but in the actual situation it's staying, sadly.