"उसने कटोरा भर दूध पिया।" (He drank a bowl full of milk). Which word is the indeclinable (Avyay) in this sentence?

In the given sentence, 'Bhar' functions as an indeclinable word (Avyay / Nipadh), which emphasizes the quantity and remains uninfluenced by gender, case, or number. 'Piya' is a verb, 'Usne' is a pronoun, and 'Doodh' is a noun. Therefore, option D is correct.