Exam SY0-601 topic 1 question 443 discussion

B is correct Key exchange is a concept in cryptography that involves the secure exchange of cryptographic keys between two parties to establish a secure communication channel. This process involves using a secure algorithm to exchange keys without exposing them to eavesdropping or interception.

Key exchange (also key establishment) is a method in cryptography by which cryptographic keys are exchanged between two parties, allowing use of a cryptographic algorithm. If the sender and receiver wish to exchange encrypted messages, each must be equipped to encrypt messages to be sent and decrypt messages received. The nature of the equipping they require depends on the encryption technique they might use. If they use a code, both will require a copy of the same codebook. If they use a cipher, they will need appropriate keys. If the cipher is a symmetric key cipher, both will need a copy of the same key. If it is an asymmetric key cipher with the public/private key property, both will need the other's public key.

Why not Point to Point Tunneling Protocol (PPTP) ? Who can explain ?