Please help with A, B and C. Full and good answer will be upvoted.

Problem 2 User Authentication a) What kind of measures are used by many computer applications to counter/stop password-guessing attacks? (1p) b) What are the two factors that affect the strength of your password? Explain how the password strength is related to each of them. (2p) c) In addition to the using of passwords, biometric information is often used to identify a person. On accessing a system with biometric authentication, a user might need to try multiple times. What is the reason for that? (2p)