1. The function $f(x)=x^{2}+2 x+3$ has a maximum value of 3 and a minimum value of 2 on the interval $[m, 0]$. The range of the real number $m$ is ( ).
A. $[1,2]$
B. $(-\infty,-1]$
C. $[-1,0]$
D. $[-2,-1]$
1. D. $f(x)=(x+1)^{2}+2, f(0)=3, f(-1)=2$, let $f(m)=3$, get $m=0$ or -2.