Concept:Use linear approximation: for a small change h, f(a+h)≈f(a)+hf′(a).Explanation:Let f(x)=3x.Then f′(x)=3xlog3=3xln3.Take a=2 and h=0.001, since 32.001=f(2+0.001).Now, f(2+0.001)≈f(2)+0.001⋅f′(2).f(2)=32=9.f′(2)=32log3=9×1.0986=9.8874.So, 32.001≈9+0.001×9.8874=9+0.0098874.Thus, 32.001≈9.0098874≈9.00989.Answer:The approximate value is 9.00989, which matches option D.