If equation 2 is true i.e, ed mod n =1, then any one can calculate private key of receiver.
Hence any one can decrypt the message of sender.
Therefore equation 2 is false.
If equation 4 is true, i.e $m=m^{e}$ mod $\phi(n)$ no one except the receiver can encrypt the message because calculating $\phi(n)$ without the prime numbers p,q which made n(i.e, n=p*q) is computationally very difficult .
Which is clearly not we want.
Hence equation 2,4 are false.
Hence option b is answer