In the following question, a sentence is given with a part highlighted. Choose the option that gives the correct replacement of the highlighted portion and makes the sentence grammatically and contextually meaningful.

Most people don’t use pine for indoor firewood because of the highly resin content.

Correct option is C

To modify the noun “resin content”, an adjective must be used, instead of an adverb as is the case in the sentence. The adverb “highly” should thus be replaced by “high”, an adjective. The correction is given by option (c), and it is thus the correct choice of answer. No other options give the required correction and thus any variations in those options are thus redundant.