If you look at the common, or shared traits of these words, you can see that all of them share one similar trait - being halved. Semicircle - half of a circle. Semifinal - test halfway through the year. Semisolid - Not liquid, but not solid either; about halfway in between.
Therefore, you can conclude that the Latin prefix <em>semi- </em>means <u><em>B.) Half</em></u>.
Slowing down and speaking clearly are both important. Slow down your speech if you're prone to talking fast. The best course of action is to keep your voice low. The usage of slang is discouraged.
