f(x)=ln[x+√(1+x^2)]
f(x)+f(-x)=ln[x+√(1+x^2)]+ln[-x+√(1+x^2)]
=ln{[x+√(1+x^2)][-x+√(1+x^2)]}
=ln(1+x^2-x^2)
=ln1
=0
f(-x)=-f(x)
且定义域是R,关于原点对称
所以选B