Final answer:
The two in ethyl alcohol, C₂H₅OH, indicates that there are two carbon atoms in each molecule of ethanol. Carbon is not diatomic in ethanol, and not all alcohol molecules contain exactly two carbon atoms, making option b the correct answer.
Step-by-step explanation:
The meaning of the two in ethyl alcohol, C₂H₅OH, relates to the number of carbon atoms per molecule of ethyl alcohol, which is option b. Ethyl alcohol, also known as ethanol, has a molecular structure of CH₃CH₂OH. This indicates that there are two carbon atoms in every molecule of ethanol, one of which is connected to an OH group (hydroxyl group), forming the functional group characteristic of all alcohols. Carbon is not diatomic in this case, so option c is incorrect. Option a is too broad and is not exclusive to ethyl alcohol, thus option b is the most accurate answer to the question provided.