Concept:Each new function adds one more logarithm, so the integrand is exactly the derivative of f2027(x).Explanation:Given f(x)=x, we have:f1(x)=f(logx)=logxf2(x)=f1(logx)=log(logx)Continuing this pattern, fn(x) contains n nested logarithms.Hence the denominator becomes:f(x)⋅f1(x)⋅f2(x)⋯f2026(x)=x⋅logx⋅log(logx)⋯f2026(x).Now observe that f2027(x)=log(f2026(x)).Differentiating using the chain rule:dxdf2027(x)=f2026(x)1⋅dxdf2026(x).Applying the chain rule repeatedly backward, each step contributes one factor from the denominator:dxdf2027(x)=f(x)f1(x)f2(x)⋯f2026(x)1.Therefore:∫f(x)f1(x)f2(x)⋯f2026(x)1dx=f2027(x)+c.Answer:Option C: f2027(x)+c