CCC is just a certificate course to understand the very basics of computing. It includes the knowledge about:
What is hardware?
What is software?
What are number systems?
What is a spreadsheet?
What is a word processor?
etc.
O-Level has something different from that of the syllabus of CCC. Moreover, O-level is equivalent to Diploma in Computer Science & Engineering (Polytechnic Diploma of 3 years). Obviously, it is not that easy but it is worthy to pursue it.
C-Programming is the major part of it.
Multimedia, ICT, etc. are other parts.