Italic and Oblique are the options here, but you could pick either one.
Well, in theory, there should be a difference …
- An italic is a specially drawn, more cursive version of a typeface.
- And an oblique is merely a slanted version of the typeface.
… but in practice, only a few fonts have both versions. (Lucida Grande seems to be one, but that’s not a web font.)
When there’s no italic version available, oblique will be used anyway (or created on the fly). That’s why I always pick
"italic", so that when a font might have both I’ll at least get the attractive option.
Italic versions of font weights can be selected in Design’s ‘Style’ menu (when a typeface has them).