How to printf “unsigned long” in C?

I can never understand how to print unsigned long datatype in C.

Suppose unsigned_foo is an unsigned long, then I try:

• printf("%lu\n", unsigned_foo)
• printf("%du\n", unsigned_foo)
• printf("%ud\n", unsigned_foo)
• printf("%ll\n", unsigned_foo)
• printf("%ld\n", unsigned_foo)
• printf("%dl\n", unsigned_foo)

And all of them print some kind of -123123123 number instead of unsigned long that I have.