My guess is they mean, one capital letter, one lower case letter, a number, and a special character

what's always amused me about these rules is that they exist because people are dumb. Technically, they lower the difficulty of the passwords slightly. ( for example, knowning that one character is a number reduces it to 10 options in stead of 10+26+26+whatever set of special characters)

anyhow. people should use password managers. just saying.