Pluralize a single letter

Source: https://developers.google.com/style/plural-single-letter

To form the plural of a single letter, italicize the letter and add an apostrophe followed by the unitalicized letter s.

• ✅ Recommended: We called tech support because the printer wasn’t printing uppercase B’s or lowercase p’s.

• ✅ Recommended: If you still use a pen and paper, dotting your i’s is still necessary. Cross your t’s, too.

When the capitalization is irrelevant, use uppercase.

• ✅ Recommended: Mind your P’s and Q’s.