The spelling rules are quite clear. (1) When the C is followed by E, I, or Y, its sound is soft like S (center, cinema, cylinder). (2) When C is followed by A, O, or U, its sound is hard like K. ( candy, cotton, cucumber). (3) When the C is the final letter, its sound is hard like K (magic, lilac, panic). (4) When the C is followed by a consonant, its sound is also hard like K (picnic, cream, click). Finally, (5), when there is a double C, the first will be hard and the second will be hard or soft depending on the letter that follows it (accord, accuse, accept, accent, vaccine).
Almost no exceptions exist to these rules, mainly some scientific words such as coelacanth and coelenterons, and a few imported words like cello (chello) from the Italian and the Gaelic word Celt (Kelt).
Students usually learn the spelling rules around the letter C early, and they usually have no trouble with it. I have always been pleasantly surprised at how quickly even the youngest students accepts the C rules.
Incidentally, Spanish spelling has similar C rules as seen in these words: caramba, corona, Cuba, crema, clima, cuidado, ciudad, centavo, cienega, cilindro.
Most of us have no problem with the soft and hard C when we read and write, and the rule comes in handy when we come across a new word and don’t know how to pronounce it.
Delete the letter C from the English alphabet? As Grandpa used to say, “If it’s not broken, why try to fix it?