单项选择题

A.(19.75-17.29)÷0.81+0.4×0.5
B.[(19.75-17.29)÷0.81+0.4]×0.5
C.[19.75-17.29÷0.81+0.4]×0.5
D.19.75-17.29÷0.81+0.4×0.5