Topic: Antonyms, Subject: English Grammar (ইংরেজি গ্রামার)

Best Answer Explained in Below-:

To understand why "controlled" forms an antonym with the prefix "un" to relate to "original," we need to clarify the meanings of these words and their components.

The term "original" refers to something that is primary, authentic, or the first of its kind. When we add the prefix "un-" to a word, it denotes negation or the opposite of that word. Thus, "unoriginal" would mean something that lacks originality or is derived from something else—essentially indicating imitation or reproduction.

Now, when we consider the provided options:

A) "appear" - relates to sight; does not form a relevant antonym.
B) "fortune" - pertains to luck or wealth; unrelated here.
C) "toxin" - refers to poison; irrelevant to the concept of originality.
D) "controlled" - suggests being managed or restricted, which can imply that something is not free-flowing or true to its nature.

When "uncontrolled" is considered, it aligns with a state of freedom or authenticity, whereas "controlled" represents a situation where the true, original form is altered or inhibited. Therefore, "controlled" can be seen as implying a lack of originality, making it the best choice for forming an antonym with "un" in this context.