The C can take on various sounds depending on what comes after it.
C + E, I or Y → [s]
(en) cancer
cancer
(ett) center
centre, center, mall
(en) cirkus
circus
(en) cykel
bicycle, bike
C + all other letters* → [k]
(ett) café
café
(en) camping
camping
(en) cancer
cancer
(en) clown
clown
(en) curry
curry
*except H which we will discuss in another lesson!