Measures must be taken before there is another collapse of the coal mine, ______?

1. A.
   must they
2. B.
   mustn’t they
3. C.
   is there
4. D.
   isn’t there

Measures must be taken before there is another collapse of the coal mine, ______?

A. must they               B. mustn’t they             C. is there                    D. isn’t there

Measures must be taken before there is another collapse of the coal mine, ______?

A. must they            B. mustn’t they          C. is there                D. isn’t there

Measures must be taken before there is another collapse of the coal mine, ______?