Lifetime for Option<struct> field


I understand the error, but I do not know how to use lifetimes to correct it.

Struct T may or may not own a S. The S uses life times for its reference field, so T needs it too. That is correct? Is it possible?

struct S<'a> {
    e:&'a usize,
struct T {
fn main() {
error[E0106]: missing lifetime specifier
 --> src/
5 |     o:Option<S>,
  |              ^ expected lifetime parameter

struct T<'a> {