The following compilation represents what facet of cryptanalysis?
A 8.2
B 1.5
C 2.8
D 4.3
E 12.7
F 2.2
G 2.0
H 6.1

I 7.0
J 0.2
K 0.8
L 4.0
M 2.4
N 6.7
O 7.5
P 1.9
Q 0.1
R 6.0
S 6.3
T 9.1
U 2.8
V 1.0
W 2.4
X 0.2
Y 2.0
Z 0.1

A.
Frequency analysis

B.
Cilly analysis

C.
Cartouche analysis

D.
Period analysis

Explanation:
The compilation is from a study by h. Becker and f. Piper that was
originally published in Cipher Systems: The Protection of Communication.
The listing shows the relative frequency in percent of the appearance
of the letters of the English alphabet in large numbers of
passages taken from newspapers and novels. Thus, in a substitution
cipher, an analysis of the frequency of appearance of certain letters

may give clues to the actual letter before transformation. Note that
the letters E, A, and T have relatively high percentages of appearance
in English text.
*Answer “Period analysis” refers to a cryptanalysis that is looking for sequences that
repeat themselves and for the spacing between repetitions. This
approach is used to break the VigenËre cipher.
* Answer “Cilly analysis” is a reference to a cilly, which was a three-character message key used
in the German Enigma machine.
* In answer “Cartouche analysis”, a cartouche is a set of hieroglyphs surrounded by a loop. A
cartouche referring to King Ptolemy was found on the Rosetta Stone.