I didn't ______ my grandparents last weekend.[ ]

A. visit                  

B. visited        

C. visiting

已知：

2CO(g)+O₂(g)=2CO₂(g) △H= -566 kJ/mol

N₂(g)+O₂(g) =2NO(g)△H=+180 kJ/mol

则2CO(g)+2NO(g)=N₂(g)+ 2CO₂(g)的△H是[ ]

A.-386 kJ/mol

B. +386 kJ/mol

C. -746 kJ/mol

D. +746 kJ/mol