Which is the correct one?

What, half, quite, rather, half, such ইত্যাদি কোন Noun বা Noun Phrase কে Modify করলে, ঐ Noun বা Noun Phrase এর পূর্বে a/an বসে।
Correct Sentences:
খ) What a wonderful bird it was!
গ) Half a loaf is better than no loaf.
ঘ) It is quite a difficult a job.