* In-: This is the most common prefix for creating negative words, and it's often used to express the opposite of something. For example, "considerate" becomes "inconsiderate".
* Un-: This prefix also means "not" and can be used to negate a word. So, "considerate" could also be "unconsiderate".
* Dis-: This prefix can mean "not" or "opposite of", and it can be used to create words that express a lack of something. While not as common, "disconsiderate" is technically a valid word.
Ultimately, the best prefix for a word depends on the specific context and the nuance you want to convey.