Concept:Use linear approximation: f(a+h)≈f(a)+hf′(a).Explanation:Let f(x)=x23.Then f′(x)=23x21.Choose a=4 and h=3.978−4=−0.022.Now, f(4)=423=8.And f′(4)=23×421=23×2=3.Using the approximation:f(3.978)≈f(4)+hf′(4)=8+(−0.022)(3)=8−0.066=7.934.Answer:The approximate value is 7.934, which is option A.