Encryption mode looks like the diagram below:where $\}\_($K$1)$:$\}$ indicates public key encryption using Key $"$K$1"$ and E$($Msg$1,$ K$2)$ indicates symmetric key encryption of $"$Msg$1"$ sing key $"$K$2"$ and h$($Msg$2)$ indicates "hash" of $"$Msg$2".$Note that R$\_$A and R$\_$B are used interchangeably with R$\_($A$)$ and R$\_($B$)$ respectively in the multiple choices below.

Q: It is possible for Trudy to create a fake conversation between Alice and Bob exactly as shown above without either Alice or Bob being involved because:

a$.$ trudy can choose exponents a and $b$ and nonces $RA$ and $RB$

b$.$ trudy can compute g$^$ab mod p just as Alice and Bob would

C$.$ trudy can encrypt messages using public keys of Alice and Bob would

d$.$ Trudy can do all of the above