python练习题选择题

不可能的选项是什么？
A.[3,9,14,22,31,20]
B.[3,9,20,13,20,27]
C.[10,19,26,29,32,39]
D.[7,17,20,13,22,12]

import random
a  = [0]*6
a[0] = random.randint(1,10)
i = 1
while i<6:
    a[i] = a[i-1]+random.randint(1,10)
    if i%2 ==0:
        a[i] = a[i]+a[i]%2
    elif a[i]%2 ==0:
        a[i] = a[i]//2
    i+=1
print(a)

答案给的是A，为什么c选项中的a[2]=26的情况下，a[3]可以等于29啊？

有啥问题呢？
第6行随机数是3就好了啊，a[3] = 26+3 = 29，后面if和elif条件都不满足啊

答案是a