【单选题】There are three main types of cryptography. 37For example, the first letters of “My elephant eats too many eels” Spell outthe hidden message “Meet me.”
A.
It is very hard to break a code without the code book.
B.
In any language, some letters are used more than others.
C.
Only people who know the keyword can read the message.
D.
As long as there have been codes, people have tried to break them.
G.
You can hide a message by having the first letters of each word spell it out. F.With a code book, you might write down words that would stand for other words. G.Another way to hide a message is to use symbols to stand for specific letters of the alphabet. F. G.