Explanation:

Explain 
Checking B-F:
He wasn't looking forward to this meeting but putting on his best behaviour anyway.
The above sentence is incorrect grammatically as ‘put’ should have been used instead of ‘putting’.
 Checking A-E:
Global markets had been roiled at the start of the week by new tariffs from the world’s two largest economies.
The above sentence is correct both grammatically and contextually.
Checking C-D:
Don't step on the broken glass else you’ll hurt yourself.
The above sentence is also correct both grammatically and contextually.
Option C is hence the correct answer.