Topic: Interchange of Parts of Speech,

Best Answer Explained in Below-:

The adjective form of "heaven" is "heavenly," and it is derived from the noun "heaven" to describe qualities or characteristics associated with this celestial concept. "Heavenly" means something that is divine, blissful, or incredibly beautiful, often evoking feelings of peace and joy that one might imagine in a perfect paradise.

Let's break down the other options:

- **A) Heave** is a verb meaning to lift or move something with effort and is unrelated to the concept of heaven.

- **C) Hellish** refers to something dreadful or akin to hell, presenting a stark contrast to the positive connotations of heaven.

- **D) Heaven** is the noun itself and does not serve as an adjective.

Therefore, "heavenly" is the correct answer because it captures the essence of the word "heaven" in an adjectival form, allowing one to convey expressions like "heavenly beauty" or "heavenly experience." This highlights its use in describing anything that relates to or resembles heaven in an uplifting or sublime way.