1. Before "a," "o," "u," and sometimes "r":
* Cat
* Coat
* Cup
* Crack
2. At the end of a word:
* Music
* Picnic
* Mechanic
3. In some words of Greek origin:
* Centrum
* Chronological
* Psychology
4. When "c" is followed by "h":
* Character
* Chaos
* Chemical
Important Notes:
* There are some exceptions to these rules. For instance, the word "ceiling" is pronounced with a "s" sound.
* In some dialects, "c" is pronounced with a "k" sound before "i" or "e" as well. However, this is not considered standard pronunciation in most English-speaking countries.
Let me know if you have any other questions!