<p>The correct answer is <strong>(C) readily</strong>.</p>
<p>In this sentence, we are comparing the availability and cost of the world supply of quick-frozen fish to the local supply. The word "more" indicates that we are looking for a word that means "easily" or "without difficulty".</p>
<p>Option (A) "heavily" means in large quantities or to a great extent. This does not fit the context of the sentence as we are not comparing the quantity of the supplies, but rather their availability and cost.</p>
<p>Option (B) "strictly" means in a precise or exact manner. This does not fit the context of the sentence as we are not discussing how the fish is frozen or supplied, but rather its availability and cost.</p>
<p>Option (C) "readily" means easily or without difficulty. This fits the context of the sentence as it indicates that the world supply of quick-frozen fish is easily available and cheaper than the local supply.</p>
<p>Option (D) "slowly" means at a slow pace. This does not fit the context of the sentence as we are discussing the availability of the fish, not the speed at which it is supplied.</p>