As it turns colder, the old are given the suggestion ________ out for physical exercise too early．

1. A.
   they shouldn’t go
2. B.
   they can’t go
3. C.
   that they not go
4. D.
   that they mustn’t go

As it turns colder, the old are given the suggestion _____ out for physical exercise too early．

A．they shouldn’t go                             B．they can’t go

C．that they not go                                  D．that they mustn’t go