Philosophy Writing

How do hypotheses like that we might be in the Matrix or brains in vats present an argument that we do not know anything?  Is that argument sound?  Valid? To answer this, be sure to…
a. Explain the hypothesis.
b. Explain its features. What does it tell us about what we know?  How can it be refuted?c c. Present an argument based on this hypothesis that we do not know anything.
d. Assess that argument.