Chọn C
Ta có:
\(\int _{1}^{5}f\left(x\right)dx =\int _{1}^{2}f\left(x\right)dx+ \int _{2}^{5}f\left(x\right)dx \)
\(\Rightarrow \int _{2}^{5}f\left(x\right)dx =\int _{1}^{5}f\left(x\right)dx- \int _{1}^{2}f\left(x\right)dx \)
\(=6-\left(-4\right)=10. \)