单选题：How many of the following statements is/are **TRUE**?
How many of the following statements is/are **TRUE**? @[A](3)
* The 0-1 knapsack problem cannot be solved by any local search algorithm.
* The metropolis algorithm always improves the gradient descent algorithm.
* In some cases, the state-flipping algorithm cannot terminate.
* Unless $$P=NP$$, there is no $$\rho$$-approximation for the maximum cut problem for any $$\rho<2$$.
A. 0
B. 1
C. 2
D. 3
A.0
B.1
C.2
D.3
答案：A
* The 0-1 knapsack problem cannot be solved by any local search algorithm.
* The metropolis algorithm always improves the gradient descent algorithm.
* In some cases, the state-flipping algorithm cannot terminate.
* Unless $$P=NP$$, there is no $$\rho$$-approximation for the maximum cut problem for any $$\rho<2$$.
A. 0
B. 1
C. 2
D. 3
A.0
B.1
C.2
D.3
答案：A