What among the following belongs to Memorability?

• A. Does the system respond with appropriate speed to a user request
• B. Can the user remember how to do system operations between users of the system
• C. How quick is it for the user to learn to use the system‚Äö√Ñ√∂‚àö√ë‚àö¬•s interface
• D. Does the system anticipate and prevent common user error?