**Which of the following explains the difference between a public key and a private key? **

A. The public key is only used by the client while the private key is available to all. Both keys are mathematically related.

B. The private key only decrypts the data while the public key only encrypts the data. Both keys are mathematically related.

C. The private key is commonly used in symmetric key decryption while the public key is used in asymmetric key decryption.

D. The private key is only used by the client and kept secret while the public key is available to all.