The second answer is correct (B).
The removal of an elected president is a pertinent device to Congress.
It is, therefore, an inquiry into the conduct of the Executive Power. However, in order to be removed, the President of the Republic must commit a crime under the American Constitution.
In case there is evidence of crime by the President, the House of Representatives is responsible for opening the impeachment process, which means giving the Federal Senate authorization to judge whether or not the president has committed the crime.
To this day, no US president has been removed by impeatchment.