.bss vs COMMON: what goes where?

Question

From my book:

.bss:

Uninitialized global C variables

COMMON:

Uninitalized data objects that are n

Answer 1

static variables end up in the .bss section.Un-initialised global variables (not static) goes in .common section.

static a;  //bss
int c;   //.common
main(){
}