given a cryptosystem S= (M,C,K,E,D), proove with shanon theorem that s is a perfect secrecy?

Question

let S= (M,C,K,E,D) be a cryptosystem with ‖M‖=‖C‖=‖K‖ and Pr(m)>0 for each m∈M. Then,S guarantees perfect secrecy if and only if

1 for each m∈M and for each c∈C, t