挑战习题
1/5单选题
难度:

1.计算的结果是(    )
A 4b
B 4
C 2b
D 2
提示1:
IDxpbWcgd2lkdGg9MTEwIGhlaWdodD00MiBzcmM9Imh0dHBzOi8vcDIucWluZ2d1by5jb20vRzEvTTAwL0E0L0JGL3JCQUNFMU9aS0VHQkJXY3NBQUFETHczekVTdzA2Ni5wbmciPg==
正确答案:RA==
6Kej77yaPGltZyB3aWR0aD0xMTAgaGVpZ2h0PTQyIHNyYz0iaHR0cHM6Ly9wMi5xaW5nZ3VvLmNvbS9HMS9NMDAvQTQvQkYvckJBQ0UxT1pLRUdCQldjc0FBQURMdzN6RVN3MDY2LnBuZyI+PGJyPuKItOmAiUQ8YnI+