A.'a'<=c1<='z'
B.(c1>='a')&&(c1<='z')
C.(c1>=a)&&(c1<=z)
D.(‘a'<=c1)||('z'>=c1)
A.97<=cl<=122
B.(97>=cl)||(122<=cl)
C.(cl>=97)&&(cl<=122)
D.(cl>='97')&&(cl<='122')
A.'A'<=ch<='Z'
B.(ch>='A')&(ch<='Z')
C.(ch>='A')&&(ch<='Z')
D.('A'<=ch)AND('Z'>=ch)
A.kk>='A'&&kk<='Z'
B.!(kk>='A'||kk<="Z")
C.(kk+32)>='a'&&(kk+32)<='Z'
D.isalpha(kk)&&(kk<91)
A.kk>='A'&&kk<='Z'
B.!(kk>='A'‖kk<='2')
C.(kk+32)>='a'&&(kk+32)<='2'
D.isalpha(kk)&&(kk<=91)
A.switch(a+b);{...}
B.switch(ch+1){...}
C.switchch{...}
D.switch(c+d){...}
A.ch>='A'&ch<='Z'
B.ch<='A'|| ch>='Z'
C.'A'<=ch<='Z'
D.ch>='A'&&ch<='Z'