"Hello, World" Key Equivocation

Given that the ciphertext KHOOR ZRUOG was encrypted using a Cæsar cipher, what is the key equivocation? Clearly there are 26 possible keys; here is the decryption of the ciphertext for each key:

key	plaintext	key	plaintext	key	plaintext
A	KHOOR ZRUOG	R	TQXXA IADXP	J	BYFFI QILFX
Z	LIPPS ASVPH	Q	URYYB JBEYQ	I	CZGGJ RJMGY
Y	MJQQT BTWQI	P	VSZZC KCFZR	H	DAHHK SKNHZ
X	NKRRU CUXRJ	O	WTAAD LDGAS	G	EBIIL TLOIA
W	OLSSV DVYSK	N	XUBBE MEHBT	F	FCJJM UMPJB
V	PMTTW EWZTL	M	YVCCF NFICU	E	GDKKN VNQKC
U	QNUUX FXAUM	L	ZWDDG OGJDV	D	HELLO WORLD
T	ROVVY GYBVN	K	AXEEH PHKEW	C	IFMMP XPSME
S	SPWWZ HZCWO			B	JGNNQ YQTNF

Assuming the plaintext is ordinary English (and not a code), the only possible plaintext is HELLO WORLD and the key is D.