Many students are confused by the C sounds. This problem can be easily solved. Please answer the questions before we know more about its pronunicaiton. 

You must feel easy to pronounce the words like cat, cost, cut, and feel no difficulty getting a conclusion: the letter C in these words is pronounced as [??]. Doest it sound [s] or [k]?1

The answer: [k]

How about these words: city, cent?2 Does the letter pronounce [k] again?

The answer: No! it sounds [s].

Then why?3

Ok, next question is: how many vowel letters in the alphabet? please tick: 3,5, 8 or 10?

Answer: 5. What are they then? 

Answer: a, e, i, o ,u. FIVE ONLY.

So, please tell how the letter C is pronounced when it is followed by different vowel letters? you can do it as long as you can pronounce the words cat, cost or city.

Got it? Yes: [k] sound happens when the letter C is followed by letters a, o, u, while it is pronounced as [s], if it is followed by letters i or e.

So far so good. But many students tend to mispronounce the letter C in new or 'strange' words. Believe it or not: Try these: century, broadcast, peculiar, civically, cease, ocean, cenote,coat, coach, celebrity, ciborium, commercial, concious, canyon, canteen, etc.

It will not be hard to pronounce any new and long words if you can follow the principle above. 

Have a good journey.