Complete the statement: Despite his best efforts to conceal his anger?

People came to know that he was annoyed

He failed to give us an impression of his agony

He succeeded in camouflaging his emotions

He could succeed in doing it easily

The phrase "despite his best efforts" indicates that someone tried very hard to do something, but ultimately failed.
In this case, the person tried to conceal their anger, but was unable to do so, and people still knew that they were annoyed.