Help me in solving CLB049 problem

My issue

sol.c: In function ‘main’:
sol.c:5:8: error: ‘c’ undeclared (first use in this function)
5 | word[c] = ‘x’;
| ^
sol.c:5:8: note: each undeclared identifier is reported only once for each function it appears in
Submit

My code

#include <stdio.h>

int main() {
  char word[] = "Ocygen";
  word[c] = 'x';
  printf("%s", word[2]);
}

Learning course: Programming and Problem solving using C
Problem Link: https://www.codechef.com/learn/course/ciet-programming-c/CIETPC12/problems/CLB049

its word[2] = ‘x’; not word[c]
one more thing if you want to print character you have to use “%c” not “%s”