The class was clear, and that made it almost what?
Options:
- murky
- confusing
- invisible
- misunderstood
- teacher Let's think step by step:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Clear glass can look invisible. Invisibility refers to not being seen. So, the answer is invisible.