please provide correct solution step by step

Consider Diffie-Hellman protocol. a. What is the Diffie-Hellman protocol used for? (5 Points) b. Given p = 13, g = 4, SA = 3, and SB = 5. Compute TA, TB, and the shared key k using Diffie-Hellman protocol. (15 Points) c. Why is Diffie-Hellman protocol vulnerable to the Man-in-The-Middle attack? (10 Points)