Select the correct option:
Their approach proved ___ effective that competitors quickly emulated it.
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. so.
Context: The sentence shows that their approach was effective to such a degree that competitors started copying it.
Meaning of the words:
So: To such a great extent or degree.
Too: More than necessary or excessive.
As: Used for comparison.
Very: To a high degree, but does not fit the required structure here.
Correct word: So
Reason: The sentence follows the structure “so + adjective + that” which is used to show result or consequence. Therefore, “so effective that” is the grammatically correct expression.
Final Sentence: Their approach proved so effective that competitors quickly emulated it.
Hence the chosen option is correct.