A：$8\times \left(1-\frac{1}{5}-\frac{3}{4}\right)=0.4\left(吨\right)$

B：$8\times \left(1-\frac{1}{5}\right)-\frac{3}{4}=5.56\left(吨\right)$

C：$\left(8-\frac{3}{4}\right)\times \left(1-\frac{1}{5}\right)=5.8\left(吨\right)$

D：$8÷\left(1-\frac{1}{5}-\frac{3}{4}\right)=160\left(吨\right)$