Which ‘but’ is a preposition?

  • It is but right to admit our faults.
  • What can we do but sit and wait?
  • We tried hard, But did not succeed.
  • There is no one but likes him.

এখানে but শব্দটি ছাড়া বা ব্যতীত অর্থে preposition হিসেবে ব্যবহৃত হয়েছে।