2.Given an integer n 2 0 , the Fibonacci number F(n) is defined as follows.

 

Whether the problem of finding a Fibonacci number F(n) is NP-complete?
(A) Yes, becausethere exists a recursive program whose running time (in units of instruction) is at least 1.618",
(B) No, because we can use an iterative approach to derive F(n) such that the running time (inunits of instruction) is about n +1；
(C) Yes, because we can use an iterative approach to deriveF(n) such that the running time (in units of instruction) is about n+1；
(D) No, because thereexists a recursive program whose running time (in units of instruction) is at least 1.618"