The answer to your question would be that the option that describes best the effect of adding the prefix pre- to a word is C, it is used to form words meaning "before (in time)".
It is a prefix originally ocurring from loanwords from Latin where it also meant "before". In addition, it is applied freely as a prefix with the the following meanings: "in advance", "prior to", "early", "beforehand", "in front of" and "before".
