$[5$ marks$]$ Suppose that $p=31,q=13,$ and you chose your encryption key to be $e=11.$ Using RSA cryptography algorithm:

a$.$ What is you decryption key $d?$

b$.$ If your professor wishes to send the plaintext message $m=365.$ What is his$/$her ciphertext?

c$.$ If your professor sends another message, and his$/$her ciphertext is c $=525.$ What was his$/$her plaintext message?