Using ‘RSA’ public key cryptosystem, if $p=3$, $q=11$ and $d=7$, find the value of $e$ and encrypt the number $’19’$

p=3, q=11 and d=7

n=pxq= 33

ϕ(n)=(p-1)x (q-1) =2x10=20

d.e = 1 mod ϕ(n)

7xe=1 mod 20 or 7e=21 =>e=3

C=P^e mod n

C=19^3 mod33

C=28

option C is right ans