(3) (2006 - Shandong) Given an odd function $f(x)$ defined on $\mathbf{R}$ that satisfies $f(x+2)=-f(x)$, then the value of $f(6)$ is ( ).
(A) -1
(B) 0
(C) 1
(D) 2
Solve $f(6)=f(4+2)=-f(4)=-f(2+2)=-[-f(2)]=f(2)$, for an odd function defined on $\mathbf{R}$, we always have $f(0)=0$, thus, $f(0+2)=-f(0)$, which means $f(2)=0$, so, $f(6)=0$, the answer is B.