In the given question, a sentence is given with a part of it missing and represented by a blank. Choose the phrase that can be placed in the given blank to make a meaningful and grammatically correct sentence.
The brakes placed on economic activities of many kinds, worldwide, __________carbon emission cuts that would previously have been unthinkable.
1
have loitered
2
have led to
3
have cluttered up
4
have venerated
5
None of these