B because a thesis statement is like a summary. This person is telling you a thing he or she did.
Theseue should be the correct answer.
For the ones like "most," you need to look at the sentence elements following to determine singular or plural. In this case, you have "most" referring to "construction," which is singular.
Answer: B. Singular
Crayfish also known as craw fish are the freshwater crustaceans. If we talk about their structure, crayfish have an adjustable eyes that can moves around in all directions, thus helping them to sense danger. Apart from this, they have antennae which helps them to discover the movements in the water.
Similarly, every living creature on this planet have varied forms of structures which allow them to be successful in their environment. Those structure could be anything- it could be either their powerful sense of smell or their sharp long teeth, it could be their powerful body or anything.