单选题：If T(n) is defined by the following recursive equation

If T(n) is defined by the following recursive equation
$$ T(n) \le T(\sqrt{n}) +c_1 $$ ($$ c_1$$ is a positive constant )
, then

@[B](2)

A. $$ T(n) = O(log_2 n) $$
B. $$ T(n) = O(log_2 log_2 n) $$
C. $$ T(n) = O(\sqrt n) $$
D. $$ T(n) = O(\sqrt{\sqrt n}) $$




A.$$ T(n) = O(log_2 n) $$
B.$$ T(n) = O(log_2 log_2 n) $$
C.$$ T(n) = O(\sqrt n) $$
D.$$ T(n) = O(\sqrt{\sqrt n}) $$


答案：B