Select the most appropriate option to fill in blank number 3.
Show answer & explanation
Correct answer: A
Explanation
The correct answer is Option 1 i.e of.
- The paragraph has a positive and informative tone.
- The preposition 'of' is used to indicate that somebody or something belongs to a group, often used after uncountable nouns such as some, a few, and so on.
- In the given sentence it is referring to the chemical compounds.
The correct sentence will be-
It is one of the most plentiful and essential of compounds.