Which of the following pairs of statements are not treated as identical by the compiler?

Which of the following pairs of statements are not treated as identical by the compiler?

1. a) int foo(int *i); int foo(int i[]);
2. b) a[i]=5; i[a]=5;
3. c) char c[10]; char *c;
4. d) void bar(int); void bar(int x);