Given the reference text, what is the female equivalent of Karl?

Carol is used as a female name, Carl or Karl is the male version of the name, although in contemporary Western usage it is more commonly used for females. It is a European continental spelling of the English Charles, the Germanic Carl, and the Latin Carolus, and can also be a short version of the name Caroline. Spelling variations include Carole.

Carol (sometimes Carole and other variations) is used a female name for Carl or Karl.