(Choose 2 answers)
Vigenère cipher is used with a key "XO" to encrypt a long English book. You order the letters encrypted book in the decreasing order of frequency (i.e., from the most frequently appearin frequently appearing), and the result is: RGZNFIBJWPESCXHTMYAUOLDKVQ. Which ciph correspond to the plaintext letter E (which is the most frequent letter in the plaintext)?
A. E
B. T
C. Y
D. Z
F
E. G
F. R
El 29
