Which one is correct?
1. Thank you for your efforts to do something ....
2. Thank you for your efforts in doing something ....
3. Thank you for your efforts of doing something ....
At first, I thought it would be either 2 or 3, but later I checked the dictionary, I am not sure now.
From the Cambridge Dictionaries Online:
[C or U] physical or mental activity needed to achieve something [+ to infinitive]
If we could all make an effort to keep this office tidier it would help.
In their efforts to reduce crime the government expanded the police force.
He's jogging round the park every morning in an effort to get fit for the football season.