Are you using the latest version?
That would mean Alpha, Numeric and Uppercase. You can select this at the screen seen in the screenshot below:
Yes but given only those options, I cannot limit the solver to only the characters "2345679ACDEFHJKLMNPRSTUVWXYZ". There are some numbers/letters that I do not want the solver to use (for example, "1", "8", "0", "B", G", etc.) since this CAPTCHA type never uses those letters... I hope that makes sense.