执行如下Python程序，运行的结果是？（ ）
def zfzh(s):
c = ''
for ch in s:
if "9">=ch>= "0":
c+=str(int(ch)+1)
elif "z">=ch>= "a":
c+= chr(ord(ch)- ord("a")+ord("A"))
return c
s = 'hzag-21-8'
print(zfzh(s))
HZAG329
923HZAG
GAZH329
923GAZH