Rogue's Key Ability Choice

The text states that "At 1st level, your class gives you an ability boost to Dexterity or an option from rogue's racket." Is this rogue racket option an additional racket from the one already given at 1st level. Or do you have to forego the Dex boost to get a rogue racket?

You have to give up the Dex boost to get the Str boost from the Ruffian or the Cha boost from Scoundrel.

But you don't have to. You can always get the Dex boost if you prefer it to Str or Cha.