The independence of the ECB is instrumental in maintaining price stability. Not only must the bank not seek influence, but EU institutions and national governments are bound by the treaties to respect the ECB's independence. To offer some accountability, the ECB is bound to publish reports on its activities and has to address its annual report to the European Parliament, the European Commission, the Council of the European Union and the European Council. The European Parliament also gets to question and then issue its opinion on candidates to the executive board.
Who gets to interview and question prospective board members?
The European Parliament