Consider a secret$-$key cryptosystem, where E is the encryption function, D is the decryption function, P is the plaintext, C is the cyphertext, and K is the key.

Determine which of the following equations hold:

Group of answer choices

D$($E$($P$,$ K$),$ C$)=$ K

D$($E$($K$,$ K$),$ C$)=$ P

D$($E$($P$,$ K$),$ K$)=$ P

D$($E$($P$,$ K$),$ K$)=$ C

D$($E$($C$,$ K$),$ K$)=$ C

D$($E$($C$,$ K$),$ K$)=$ P

D$($E$($K$,$ P$),$ K$)=$ C