下列哪个语句段的时间复杂度最低？

if n%2==0:

x=x*2

else:

x=x+2

n=1

while n<=100:

x=x+2

for i in range(100):

for j in range(10):

    x=x+2

for i in range(100):

for j in range(i):

    x=x+2