Givenm, n∈Z, define f(x)=log 2 (4-|x|) in the interval [m,n]. The value range of f(x) is [0,2]. If there exists only one zero point on g(x)=2|x-1|+m+1,then m+n=( )。 (A)-1. (B)0. (C)1. (D)2. (英汉小词典:interval区间;valuerange值域)