Fill in the blank with the appropriate adverb out of the options given below:

I have never heard of this _____.

(A) forward
(B) backward
(C) yesterday
(D) before

Choose the correct answer from the options given below:

(D)

The correct answer is Option (2) → (D)

The sentence "I have never heard of this _____." requires an adverb that means "at any time in the past."

• "Before" is the correct choice because it means "at an earlier time", which fits perfectly in this sentence:
  "I have never heard of this before."

OTHER OPTIONS

• (A) Forward  → This means "ahead" in direction or progress, which does not fit the sentence.
• (B) Backward  → This means "in the opposite direction", not related to hearing something before.
• (C) Yesterday  → This refers to a specific day in the past, but the sentence is about any time in the past rather than just yesterday.