The answer would be A because a virus is surrounded in a protein coat
Total addressable market is defined as the size of the revenue opportunity that is available for a product or service. The estimation of the market can be based on the size of the market a company can gain if there is no competitor. Total addressable market is usually given in numerical form and it represents the global total of that particular market. The total addressable market is $540 million annually is correct for this question.
